Knuckles the Echidna

"I'll probably be on this floating island forever, guarding the Master Emerald again. I may not know the whole story behind this, but perhaps it's better that way."

- Knuckles the Echidna, Sonic Adventure

Knuckles the Echidna (ナックルズ・ザ・エキドゥナ) is a fictional character from the Sonic the Hedgehog series. He is an anthropomorphic sixteen-year-old red echidna and the current guardian of the Master Emerald, a powerful ancient relic which is his solemn duty to protect from anyone who wants to abuse it. He is also the sole remaining descendant of the Knuckles Clan and last of the echidnas on earth. His dominant traits are his superhuman strength, and the two spike-like knuckles on each of his hands, from which his name is derived from, which he can use to dig with and climb up walls with ease. He can also trap the wind under his dreadlocks to glide through the air.

A loner by nature, Knuckles is independent, headstrong and serious, yet gullible and short-tempered to a fault. He is fully devoted to his duty, spending most of his time on Angel Island protecting the Master Emerald, and rarely cares for anything that is not important. When his friends and others are in need of his help, however, Knuckles can always be relied on being willing to leave his post and prove himself a true and good-hearted hero. He is also one of Sonic's oldest friends and rivals.

According to official Sonic Team polls, Knuckles is the fourth most popular character in the series, behind Tails, Shadow and Sonic.

Concept and creation
Knuckles was originally created and designed by Takashi Thomas Yuda. During the conception of Sonic the Hedgehog 3, the development team wanted to create a new rival for Sonic. The final design of Knuckles was the result of dozens of possible designs inspired by numerous different animals. The emphasis of the character was to break walls. Knuckles' shoes are based on the colors of the Jamaican flag, and his appearance is overall Jamaican. In fact, he was originally meant to speak with a Jamaican accent.

Early Life
Knuckles was born and raised on Angel Island. He is the last surviving member of the remainder of the Knuckles Clan, a long-lost tribe of echidnas, which devoted themselves to protecting the Master Emerald after Pachacamac incurred the wrath of Perfect Chaos who nearly completely wiped them out 4,000 years ago.

Despite his peoples' colorful history, Knuckles' own past was a mystery to him; he did not know how he came to be, nor what other reasons he had for existing, and he believed himself to be the last of his kind entirely. The only thing Knuckles knew that for as long as he could remember, he had been living on Angel Island, protecting the Master Emerald. He did not know why he was compelled to fulfilling this task, only that it was his sworn duty and fate to protect the Master Emerald from anyone who wanted to abuse it. As far as Knuckles knew, this was his purpose in life, and he was content with that.

For much of his life, Knuckles stayed close to the Master Emerald's shrine, steadfastly protecting the Master Emerald while having little to no contact with the outside world. Over time, Knuckles became friends with all the animals and the nature itself on Angel Island.

Sonic the Hedgehog 3
In Sonic the Hedgehog 3, Knuckles was on his usual patrol of the island's pillar, watching over the Master Emerald and the seven Chaos Emeralds. Just as he was making sure that the Chaos Emeralds were in place, however, the Chaos Emerald before his eye began to float as tremors started to occur. Confused at this unique phenomenon on his island, Knuckles witnessed the Chaos Emeralds starting to vibrate violently as the tremors grew worse. When the tremors reached their climax, Knuckles heard an ear-piercing crash just as a brilliant flash filled his vision. Then, without warning, Knuckles was thrown out of the altar and fell unconscious.

When Knuckles later came to, he discovered that he was outside, only to see that the altar had been partially destroyed. He flew back to the altar, where he discovered that the Chaos Emeralds had disappeared. Shocked and in a daze, Knuckles left the altar and quickly began traversing the rest of the island. Gazing into the horizon, Knuckles saw the Death Egg which had crash-landed on Angel Island, its impact having pushed the island into the sea and caused the tremors. Seeing the Death Egg made Knuckles recall a prophecy depicted on murals in the Hidden Palace Zone that said that a dragon would bring disaster to the island. Recognizing the Death Egg as that dragon, Knuckles feared that the prophecy had come true.

Over the next few days, Knuckles patrolled the island while investigating the altar, hoping to find the Chaos Emeralds, but without luck. Eventually, he came across Dr. Ivo Robotnik in the woods during his search. The doctor introduced himself as a scientist conducting research on the Death Egg to prevent disaster, before telling that two people, named Sonic and Tails, were out to steal the Master Emerald. Due to his seclusion, Knuckles believed Robotnik and made it his goal to stop Sonic and Tails while keeping them from getting to Robotnik, not realizing that he was being used by Robotnik to keep Sonic and Tails at bay while he rebuilt the Death Egg.

When Sonic arrived on the island as Super Sonic with Tails, Knuckles pulled a cheat shot on Sonic that forced the Chaos Emeralds out of him. Knuckles then escaped with the Chaos Emeralds and hid them away across the island, before turning his attention to Sonic and Tails.

As Sonic and Tails continued to travel across Angel Island, Knuckles attempted to stop the duo in Angel Island Zone, Hydrocity Zone, Carnival Night Zone and Launch Base Zone with his traps. When Sonic then tried to to board the Death Egg, Knuckles kept Sonic from getting close until tremors caused Knuckles to trip and fall.

Sonic & Knuckles
In Sonic & Knuckles, after the Death Egg crash-landed on Angel Island again, Knuckles returned to the Hidden Palace Zone. After having finished his errands there, Knuckles used a Giant Ring to get to the Mushroom Hill Zone. After securing the hidden room (not aware that Sonic and Tails were watching), Knuckles disappeared into the forest.

Seeing that Sonic and Tails were still exploring the island, Knuckles continued to try and stop them with traps in Mushroom Hill Zone and Lava Reef Zone. However, when Knuckles found Sonic and Tails arriving in the Hidden Palace Zone, he faced Sonic in an epic showdown, but was defeated. After his defeat, Knuckles heard an explosion at the shrine and went to check the Master Emerald. There, Robotnik's betrayal was revealed to Knuckles, as he saw Robotnik had broken into chamber and was stealing the Master Emerald to power the Death Egg. Realizing he had been tricked, Knuckles tried to get the Master Emerald back, but was electrocuted, and Robotnik escaped. Understanding they were on his side, Knuckles guided Sonic and Tails to the Sky Sanctuary Zone from where they could board the Death Egg.

Once arriving in the sanctuary, the trio witnessed the re-launch of the Death Egg. Knuckles, however, was too exhausted from the previous struggles, so he could only lead Sonic and Tails on their way. Fortunately, Sonic and Tails returned with the Master Emerald and Angel Island returned to the sky where it belonged. Knuckles then watched on contently as Sonic and Tails left the island in the Tornado.

Unfortunately for Knuckles, the newfound peace came to a halt when one of the EggRobos, under orders from Robotnik to eliminate Knuckles, went to attack the echidna. While he was relaxing in the Mushroom Hill Zone, Knuckles was suddenly ambushed when EggRobo dropped a bomb in front of him. Though luck or toughness, Knuckles survived the explosion and saw his attacker. Enraged, Knuckles set off to defeat EggRobo.

After casing the robot across his island, Knuckles followed it to Sky Sanctuary Zone where he was ambushed by EggRobo, who grabbed Knuckles with his Egg Mobile. Knuckles was then brought before Mecha Sonic, who had stolen the Master Emerald for its own ends, causing Angel Island to wobble in the sky and threatening to fall. Before Mecha Sonic could kill Knuckles, the echidna escaped the Egg Mobile, resulting in EggRobo's destruction, and he began his showdown with Mecha Sonic. As the battle continued, Mecha Sonic harnessed the Master Emerald's power to become Super Mecha Sonic, but Knuckles still defeat it, though the battle caused their battle ground to crumble.

Fortunately, Knuckles and the Master Emerald were rescued from their fall when Sonic arrived in the Tornado and caught Knuckles and the Master Emerald on the plane. Thanking Sonic for his help, the two of them returned to Angel Island where they brought the Master Emerald back into place. Having saved Angel Island again, Knuckles and Sonic departed ways once more.

Sonic the Hedgehog Triple Trouble
In Sonic the Hedgehog Triple Trouble, Knuckles met Dr. Robotnik, who tricked him into believing that Sonic and Tails were out to steal the Chaos Emeralds for their own ambitions, not realizing he was being used to gather the Emeralds for Robotnik and as well to deal with Sonic. As such, Knuckles began to search for the Chaos Emeralds and stop Sonic.

Acting in good time, Knuckles found the five lost Chaos Emeralds first, which were then hid away in the Special Stages. When Knuckles later found Sonic and Tails as the duo was searching for information on the Chaos Emeralds, he appeared before them and blocked their path, where he told Sonic spitefully that he would never get his hands on the Emeralds, before making his escape.

After their encounter, Knuckles tried to hinder Sonic and Tails' quest to retrieve the Chaos Emeralds with traps in Great Turquoise Zone, Meta Junglira Zone and Robotnik Winter Zone. In Tidal Plant, however, Knuckles faced Sonic and Tails head on, here using an underwater vehicle, but was defeated.

Following his defeat, Knuckles was trapped inside a cage in the Atomic Destroyer Zone by Robotnik. Later, after Sonic and Tails had defeated Robotnik, Knuckles was freed from his captivity by the duo, and Knuckles made up on good terms with his friends once more, before taking his leave.

Knuckles' Chaotix
In Knuckles Chaotix, a few months after the events of Sonic & Knuckles, Knuckles noticed a new island had risen from the southern ocean as a result of tectonic activity simulated by the Master Emerald's presence when Angel Island sank into the sea. What irked Knuckles even more was that the energy from the Master Emerald's pillar was rapidly transforming the island from a barren rock into a tropical paradise. Annoyed with questions, Knuckles believed that something on that island was causing this and speculated it held the remains of a legendary civilization that perished long ago. Realizing something on the island was resonating with and amplifying the Master Emerald's pillar, Knuckles, ever devoted to his duty, went to investigate the island.

When Knuckles got to the island, he noticed that it had been converted into the Newtrogic High Zone by Dr. Robotnik, who had arrived on the island to synthesize Dark Rings that would allow the doctor to summon the Master Emerald and conquer the world. After arriving, Knuckles found Robotnik, who was trapping Espio the Chameleon in his Combi Catcher and scare the doctor off. Knuckles then freed Espio and saw Robotnik leave with Metal Sonic. Knuckles and Espio then decided to team up to free Robotnik's other captives, collect Robotnik's Chaos Rings, and stop Robotnik.

Together, Knuckles and Espio freed Robotnik's other captives, namely Vector the Crocodile, Charmy Bee and Mighty the Armadillo, who joined them in their mission, forming the Chaotix. The group was also joined by two of Robotnik's rogue robots Heavy and Bomb. Eventually, Knuckles and his group got six Chaos Rings before Robotnik, and stopped the scientist's usage of the Dark Rings on several occasions.

Eventually, Knuckles and the Chaotix were attack by Metal Sonic, who they managed to defeat, though the resulting battle caused them all to fall into a closed battle arena. There, Knuckles and the others were attacked by a large, Metal Sonic-like robot, Robotnik's final trump card. Regardless Knuckles and the Chaotix still defeated it, thus ending Robotnik's plans and restoring peace to the island.

Sonic the Fighters
In Sonic the Fighters, Dr. Robotnik built the Death Egg II from where he planned to conquer earth. To face this threat, Knuckles entered a fighting tournament where the winner got to collect all the Chaos Emeralds from the other participants, with himself possessing one Chaos Emerald already. Should he win all the Chaos Emeralds, Knuckles would earn the right to use the Emeralds to power Tails's single-seat Lunar Fox and use it to travel to the Death Egg II and destroy it.

At the end of the tournament, the victor got all the Chaos Emeralds and used them to go to the Death Egg II in the Luna Fox. There, the victor defeated both Metal Sonic and Robotnik using the Emeralds and rigged the Death Egg II to self-destruct before heading back to earth in the Luna Fox moments before the massive space station exploded.

Sonic 3D Blast
In Sonic 3D Blast, Knuckles joined Sonic and Tails on their journey to Flicky Island. Having heard legends that the Flickies on the island held the key to finding the Chaos Emeralds, Knuckles, Sonic and Tails traveled there in hopes of finding these gems. When the trio finally arrived on the Flicky Island, however, Knuckles and the others found the whole place in disarray. It turned out that Dr. Robotnik had arrived on the island before them and established a base there, from where he trapped the native Flickies in his Badniks and used them to search for the Chaos Emeralds, which happened to be located on the island. Learning of the doctor's nefarious plans, Knuckles and the others decided to put a stop to Robotnik's plans by freeing the Flickies from their captivity, return them to their home dimension, and collect the Chaos Emeralds first.

While Sonic traveled across the island, freeing the Flickies, Knuckles and Tails helped Sonic find the Chaos Emeralds by taking him to their locations. With Knuckles and Tails' assistance, Sonic was successful in freeing the island from Robotnik's tyranny, and bringing peace back to the island.

Sonic R
In Sonic R, Knuckles heard from some global advertisement that the World Grand Prix, a racing competition to determine the fastest in the world, was about to take place. Once he learned that Sonic was going to participate, Knuckles entered the World Grand Prix himself, not willing to miss the chance to settle his score with Sonic once and for all.

During the World Grand Prix, Knuckles not only went up against Sonic, but also Tails, Amy Rose and Dr. Robotnik and his lackeys, who were using Knuckles and his friends to locate the Chaos Emeralds which were located on the race tracks. At the end of the tournament, Knuckles and the heroes managed to keep Robotnik from getting the Chaos Emeralds, ensuring the world's safety once more.

Sonic Blast
In Sonic Blast, Knuckles teamed up with Sonic when Dr. Robotnik planned to use the shattered pieces of a Chaos Emerald to fortify his Silver Castle. In the end, Knuckles and Sonic secured the Emeralds and stopped Robotnik's plans, and Knuckles watched contently from afar as the doctor's fortress crashed.

Sonic Adventure
In Sonic Adventure, in the dusk of night, Knuckles was sitting beside the Master Emerald at its altar, drifting to sleep while lamenting the story of his life. Suddenly, he was awakened by a noise, and found Chaos next to the shattered Master Emerald. Shocked and enraged at the damage done to the relic, Knuckles assumed that Chaos was behind it and attacked it, but it blindsided Knuckles and sent him flying off the altar, before escaping. Because of the Master Emerald's absence, Angel Island fell into the sea.

Knowing that the Master Emerald could be restored if he found all its fragments, Knuckles left Angel Island to search for its wide-scattered Emerald Shards. After finding the Emerald Shards in Speed Highway and Casinopolis in Station Square, Knuckles was pulled into the past of the Mystic Ruins when the Knuckles Clan was still thriving, by Tikal's spirit. While there, Knuckles witnessed Tikal's futile attempts to convince Pachacamac of abandoning his warmongering ways, before he was sent back to the present.

Confused about what had happened, Knuckles spotted Dr. Eggman and a shine in doctor's hand, which Knuckles believed to be an Emerald Shard. After cornered Eggman, however, Knuckles saw that the doctor possession was a Chaos Emerald, before giving it to Chaos 1, transforming it into Chaos 2. Recognizing the creature, Knuckles attacked and defeated Chaos 2. After the battle, Knuckles was told by the departing Eggman that Sonic was after the Emerald Shards too. Wondering why Sonic wanted the shards, Knuckles decided to find Sonic to get some answers.

After finding more Emerald Shards in Red Mountain, Knuckles found Sonic and Tails. Seeing a shine in Sonic's hands, Knuckles believed it was Emerald Shards, and attacked them, demanding the Emeralds back. Knuckles then fought Sonic for a while until Sonic lost his two emeralds, for then to have Eggman nab them. Knuckles saw that they were actually Chaos Emeralds and was surprised when Eggman revealed that he had tricked him so he could steal the Chaos Emeralds. Eggman then gave the Chaos Emeralds to Chaos 2, causing it to transform into Chaos 4, but Knuckles, Sonic and Tails defeated Chaos 4. As Eggman left in the Egg Carrier, with Sonic and Tails going after him, Knuckles went to find the rest of the Emerald Shards.

After finding more Emerald Shards in Lost World, Knuckles was sent back to the past again, where he saw Tikal attempt to make Chaos leave the Altar of the Emeralds with the Chao. Knuckles was then sent back to the present again, in front of the present-day alter. There, Knuckles tried to restore the Master Emerald, but saw it was still missing a few pieces. Knuckles then saw the Egg Carrier's image in the Master Emerald and deduced that it was the location of the last Emerald Shards.

As he left the altar, Knuckles spotted E-102 Gamma and decided to trail the robot to the Egg Carrier. On the Egg Carrier, Knuckles found the last of the Emerald Shards and prepared to return home, but was then sent to the past again, where he found the alter ablaze. He walked over to Tikal and attempted to find out what was going on, but was sent back to his own time. Back on the Egg Carrier, Knuckles tried to leave, but then spotted Eggman and Sonic. Meeting with Sonic, who went after Eggman shortly after, Knuckles fought and defeated Chaos 6, making it relinquish the six Chaos Emeralds it had absorbed. When the Egg Carrier then began to self-destruct, Knuckles glided back to Angel Island with the six Chaos Emeralds. Back at the Island, Knuckles fully restored the Master Emerald, allowing the giant gem to hoist Angel Island back to the heavens.

Not long after, however, the Angel Island soon fell back down from the sky again. Knuckles, baffled as to why this had happen, decided to find Sonic for advice, believing the Chaos Emeralds he had brought back with him had something to do with it. Soon after, however, he found Eggman beaten up, before being ambushed by Chaos, who took his Chaos Emeralds. Knuckles was later found by Sonic and Tails and he informed them of Chaos's return and warned them that Chaos would destroy the world with the Chaos Emeralds, before telling them to keep the last Emerald safe. Knuckles then took off himself to deal with the threat.

Knuckles later traveled to Station Square where Perfect Chaos was on a rampage. There, he found four of the now-drained Chaos Emeralds and brought them to Sonic while his other friends brought the remaining three, where he somewhat reluctantly agreeed with Tails that Sonic could still harness the Chaos Emeralds' positive Chaos Energy to stop Chaos. Knuckles then saw Sonic transform into Super Sonic and defeat Perfect Chaos. After the battle, Knuckles looked on with content as Chaos was returned to a peaceful creature once more and departed with Tikal.

Sonic Shuffle
In Sonic Shuffle, Knuckles was hanging out with Sonic, Tails and Amy, when they were without warning transported to Maginaryworld. Landing in the Temple of Light, Knuckles and the gang met Lumina Flowlight, the one bringing them to Maginaryworld. After presenting Maginaryworld, Lumina explained they here to help her restored the Perfect Precioustone which had been shattered by Void. Its pieces were then scattered to different part of this world and had made the world's guardian and protector of the Precioustone, Illumina, disappear too. If the Perfect Precioustone was not restored, Void's darkness would destroy Maginaryworld with corruption. Along with the others, Knuckles agreed to help, remarking that he got nothing better to do.

Starting their adventure, Knuckles and his friends began recovering the Precioustone pieces from the different worlds within Maginaryworld and restoring the places affected by Void. Whenever they got a Precioustone, Knuckles and his friends had a dream where he met Void. In these dreams, Knuckles and the others initially opposed Void, but they soon saw that Void was lonely and depressed which touched their hearts, and they eventually realized that Void and Lumina embodied the positive and negative aspects of dreams and were two halves of the same being.

After returning the missing Precioustones to the Temple of Light, Knuckles and the others went back to the temple when Void headed there to seek out the Perfect Precioustone again. When they got to the temple to stop Void, Void claimed he just want to become whole, but never could. With Knuckles and the others rejecting him, Void’s loneliness and despair reached its peak and he transformed into a monster.

Knuckles, Sonic and Tails and Amy fought and defeated Void, but Lumina gave into despair as the Perfect Precioustone was not recovering, despite Knuckles telling her it could not end like this. When Sonic found Void in the form of a dark gem, the group tried to make Lumina accept Void and that negative feelings were needed for dreams, with Knuckles telling her that people only lose their dreams when they give up on themselves, a fact he noted Lumina should know all about. Having cheered Lumina up, Knuckles and the group witnessed Lumina restoring the Precioustone, and Lumina and Void resuming their original form, Illumina. As Marginaryworld was restored to an even better place, Knuckles and the gang received Illumina's gratitude before returning to their own world.

Sonic Adventure 2
In Sonic Adventure 2, Knuckles discovered that the Master Emerald had been stolen by Rouge the Bat. Tracking her to a desert area, Knuckles confronted Rouge and got into an argument with her about the ownership of the Master Emerald, when the gem was suddenly stolen by Dr. Eggman, who arrived hoping to find the Chaos Emeralds. When Eggman tried to escape, Knuckles purposely shattered the Master Emerald, scattering its Emerald Shards to prevent the theft. Knuckles was berated by Rouge for smashing the Master Emerald, but Knuckles stood by his action.

Beginning his search for the Emerald Shards, Knuckles found some in Wild Canyon, Pumpkin Hill and Aquatic Mine by following their signals. Along the way, Knuckles got lost in the tunnels inside Aquatic Mine and ended up in Central City. There, Knuckles met Tails and Amy, only for Amy to drag him into Sonic's latest adventure, where they were trying to stop Dr. Eggman from using the Eclipse Cannon to take over the world.

Having located Eggman on Space Colony ARK, Knuckles led the group to Eggman's pyramid base, having seen both Eggman and Rouge enter it. Believing there was a space shuttle in there that they could use to get to Space Colony ARK and destroy the Eclipse Cannon, Knuckles and the others infiltrated the base. After finding the keys to the center of the base at Sonic's choice, Knuckles faced and beat King Boom Boo. After gaining access to the launch pad of the shuttle, Knuckles and the others were ambushed by Eggman with the Egg Golem. While Sonic defeated the Egg Golem, Knuckles and the others got a space shuttle for them to use.

While en route to Space Colony ARK, the group's space shuttle hit a stray asteroid, causing the cargo bay to open and releasing all Knuckles' Emerald Shards which he had stored there. Panicking, Knuckles tried to take control of the shuttle, only to cause it to crash on Space Colony ARK. After landing, Knuckles left the group to find the lost Emerald Shards.

After finding some Emerald Shards, Knuckles met Rouge again and fought her to a stalemate. however, Knuckles saved Rouge's life when she tripped and nearly fell into a magma pit. Despite this, Knuckles was still berated Rouge, which infuriated him. Regardless, Rouge returned her Emerald Shards to Knuckles as thanks, and Knuckles restored the Master Emerald. As he left, Knuckles swallowed his pride and apologized to Rouge in the case he hurt her.

Back inside the ARK, Knuckles witnessed Sonic appearing in front of him with Chaos Control when he escaped from an exploding capsule with a fake Chaos Emerald. Knuckles was then told by Sonic to go help Tails and Amy, before Sonic left to destroy the Eclipse Cannon.

After the Eclipse Cannon was stopped, Knuckles and Sonic met Rouge, who told them that the ARK was on a collision course with earth. Knuckles and the others then saw a recording of Gerald Robotnik announcing to the world that the ARK's impact would destroy the planet as his revenge at the world for the death of his granddaughter, Maria. Banding together with Eggman, Knuckles and the group came up with the plan to use the Master Emerald to deactivate the seven Chaos Emeralds, which was powering the cannon's core, to stop the Space Colony's crash course.

When Knuckles and Sonic made it to the core, they were attacked by the Biolizard, but Shadow arrived and held it off. Knuckles then used the Master Emerald and neutralized the Chaos Emeralds. In response, however, the Biolizard warped outside the ARK and merged with it, becoming the Finalhazard and kept the ARK on its collision course. Knuckles then saw Sonic and Shadow using the Chaos Emeralds to become Super Sonic and Super Shadow, and gave them advices through transmission lines.

After Super Sonic and Super Shadow defeated the Finalhazard and brought the Space Colony ARK back into orbit, Knuckles and the others found Sonic returning alone, informing them that Shadow had seemingly died. Knuckles then asked Rouge what she planned to do next and was content to hear she considered giving up her treasure hunting profession. Soon after, Knuckles and the others returned to earth.

Sonic Advance
In Sonic Advance, Knuckles joined forces with Sonic, Tails and Amy to stop Dr. Eggman from obtaining the seven Chaos Emeralds. Over the course of their adventure, Knuckles and the others got the Chaos Emeralds first and chased the doctor to the X-Zone. After they defeated the EGG X, Knuckles, Tails and Amy returned to Earth while Super Sonic faced Eggman in a final confrontation on the moon. There, they awaited Sonic's return, but grew confused when he did not show up. A few days later though, Sonic finally returned.

Sonic Advance 2
In Sonic Advance 2, Knuckles was kidnapped alongside Tails by Dr. Eggman when the evil scientist attempted once more to create the Eggman Empire. After being captured, Knuckles was somehow tricked by Eggman into fighting Sonic.

In Sky Canyon, Knuckles intercepted Sonic and his allies in the Egg Saucer, but was defeated. Realizing that he had been tricked, Knuckles tried to defend himself, but was chided by Sonic. When Sonic then tried to leave, Knuckles joined him, wanting payback at Eggman.

After hunting down and seemingly beating Eggman, Knuckles, Sonic, Tails, Cream and Cheese found Vanilla who had gone missing, only to see her being kidnapped by Eggman in his new mech. Knuckles then witnessed Sonic using the Chaos Emeralds to become Super Sonic and taking off to rescue Vanilla and stop Eggman. When Sonic returned with Vanilla, Knuckles congratulated Sonic for a job well done.

Sonic Advance 3
In Sonic Advance 3, where the Earth was split into seven regions by a massive Chaos Control induced by Dr. Eggman, Knuckles met Sonic and Tails in Sunset Hill. Seeing the trouble going on, Knuckles offered his help, but Sonic declined it. Regardless, Knuckles still joined them.

Traveling across the different regions, Knuckles and his friends eventual got the seven Chaos Emeralds and had Amy and Cream join them. Along the way, Knuckles also faced Dr. Eggman's newest creation, Gemerl, a rebuilt version of Emerl. Eventually, Knuckles and his friends got to the Emerald Altar where they beat the Hyper EggRobo and used the Master Emerald to return the world to normal. Later, following Sonic's return from his and Eggman's battle with Ultimate Gemerl, Knuckles remained behind at the Master Emerald's shrine and watched on satisfied when his friends took their leave.

Sonic Heroes
In Sonic Heroes, Knuckles and Tails received a letter from Dr. Eggman, who claimed to have created "the ultimate weapon" to conquer the world and challenged them to stop him within three days. Using the Tornado 2, Knuckles and Tails found Sonic and brought him the news. As Knuckles was confident they could handle it, he and Tails joined Sonic in stopping Eggman's scheme, officially forming Team Sonic.

Beginning their mission by tracking Dr. Eggman, Team Sonic found the doctor at Ocean Palace, where they were attacked by the Egg Hawk. Though the team defeated the machine, Eggman escaped. Knuckles and Team Sonic then followed Eggman to Grand Metropolis, where the team freed the city from Eggman's control and escaped from the Power Plant, before running into Team Rose, who they managed give the slip.

Arriving in Casino Park, Knuckles was taken back by the place, but was pushed on. As they got through the city, Eggman attacked them with his Robot Carnival, but Team Sonic defeated the horde. Following Eggman to Rail Canyon and only having until sunset, Knuckles and his team headed for Bullet Station and destroyed Eggman's base there. Team Sonic found Eggman in the Egg Albatross and destroy it. It was then, however, that Knuckles and the team discovered that the Eggman they had been chasing was a copy, and that their challenge was to distract them while Eggman launched his Egg Fleet. As Sonic took off, Knuckles quickly followed him.

Following Eggman through the jungle, Team Sonic met Team Dark and saw Shadow was still alive. As an argument arose about who would case Eggman, the two teams fought each other. After the battle, Team Sonic followed Eggman and Shadow to Hang Castle, where Knuckles teased Tails by saying that it could have been Shadow's ghost they saw. After infiltrating the castle and escaping Mystic Mansion, Team Sonic was attacked by Eggman's Robot Storm, but defeated it.

After that, Team Sonic got to the Egg Fleet and went straight for the Final Fortress where they destroyed the colossal flagship's core. Team Sonic then found Eggman in his Egg Emperor and defeated him. After destroying much of the Egg Fleet, Knuckles teased Sonic with how he would had stood no chance without their help, but was surprised when Sonic agreed. Knuckles and Tails then watched Sonic escaping as Amy arrived.

Later, Team Sonic and the other teams saw the return of Metal Sonic, who had been staging the team's adventures and impersonating Eggman so he could follow them and copy their data in a plan to conquer the world himself, as he transformed into Metal Madness. Seeing that the teams had collected all the Chaos Emeralds, the real Dr. Eggman came up with the plan of using them against Metal Sonic. When Sonic decided to face Metal Sonic alone, Knuckles insisted on going with him along with Tails. While Team Sonic charged the Chaos Emeralds, Team Rose, Dark and Chaotix fought Metal Madness to buy them some time.

When Metal Madness transformed into Metal Overlord, Knuckles and Tails got a Super Shield from Sonic as he transformed into Super Sonic. The team then took off and defeated Metal Overlord. Back on the flagship, Knuckles watched Sonic leave, before chasing after Rouge once she said she would steal "someone else's treasure." Soon after, Knuckles joined Sonic and Tails as they headed off to find their next adventure.

Shadow the Hedgehog
In Shadow the Hedgehog, Knuckles left his post on Angel Island and joined forces with most of his friends and G.U.N.'s forces to repel the Black Arms invasion of Earth. He appears during Shadow's Hero Missions where he asks Shadow for assistance against the Black Arms.

Glyphic Canyon
Arriving in Glyphic Canyon, Knuckles attempted to assist G.U.N. by driving off the Black Arms infesting the area. There, he met Shadow, who had just been teleported to the ruins. Upon meeting him, Knuckles filled Shadow in on the Black Arms around them, and requested his assistance in clearing the area of the Black Arms.

In the Hero scenario, where Shadow accepted Knuckles' request, Knuckles and Shadow managed to drive the Black Arms out of the area, and as well finding one of the Chaos Emeralds amongst the ruins.

Central City
In Central City, Knuckles discovered that the Black Arms had set up bombs across the city that would destroy the entire city, a tragedy that Knuckles did not intend to come true. When there was only a few minutes left until the bombs would explode, Knuckles noticed Shadow had arrived in Central City and asked for help defusing the bombs.

In the Hero scenario, where Shadow accepted Knuckles' request, Knuckles and Shadow succeeded in defusing enough bombs and managed to save the city.

Black Comet
Having gotten onboard the Black Comet, Knuckles assisted G.U.N. in attacking the Black Arms' base, with Knuckles planning to destroy the comet's core. On his way to the core, Knuckles came across Shadow and asked him for his help to get to the center.

In the Hero scenario, where Shadow accepted Knuckles' request, Knuckles and Shadow made it to the center of the Black Comet, where they found the Chaos Emerald that the Black Arms had stolen. Though Shadow refused to follow Knuckles any further, Knuckles still came to Shadow's aid when the hedgehog was attacked by Dr. Eggman and his Egg Dealer. Eventually, the two destroyed Eggman's contraption and as well claim the final Chaos Emerald.

Last Story
In the last story, Knuckles arrived with Sonic, Tails, Amy, Rouge and Dr. Eggman to stop Shadow from giving the Chaos Emerald to Black Doom. Black Doom however, took the Emeralds and used an enhanced Chaos Control to transport the Black Comet to the surface, planning to use humans as energy sources for his kind. As Knuckles prepared to act, he and the others were paralyzed by a special nerve gas and Black Doom unleashed the Death leeches to prey on them. Shadow however, proved to be immune to the gas, and he left Knuckles and the others behind as he pursued Black Doom.

Knuckles and the others eventually escaped the Black Comet and found some shelter from where they cheered Super Shadow on as he fought and defeated Devil Doom. Knuckles then witnessed Super Shadow sending the Black Comet back into space and blowing it up with the Eclipse Cannon. As Eggman then tried to sneak away to claim the Chaos Emeralds, Knuckles furiously chased after him.

Sonic Battle
In Sonic Battle, Knuckles heard from the news that an E-121 Phi had been robbing jewelry stores. Later, Knuckles met Sonic and Tails and Emerl, a Gizoid Sonic had found, who had come to ask for the Chaos Emerald in his possession to develop Emerl. Knuckles, however, mistook Emerl for the E-121 Phi and attacked him, but was defeated. Knuckles then relinquished his Chaos Emerald and heard about Emerl's abilities and that Eggman and Rouge were after him, making him suspicious.

Later, Knuckles met Tails and Emerl, where he, after a brief fight with Emerl, was then told by Tails to come to Emerald Beach when their path was blocked by Chaos Gamma. In the end, Knuckles took care of Gamma alone, allowing Tails and Emerl to leave. When Chaos Gamma escaped, Knuckles got to Emerald Beach, where he saw Rouge leave and heard what had happen from Sonic. When Knuckles tried to ask Emerl, he became infuriated as Emerl continued to ignore him, especially upon Sonic's orders, which made Knuckles fight both of them.

Later, after Emerl had been stolen by Rouge, Knuckles and Tails aided Sonic when he fought Rouge to get Emerl back, with Rouge eventually surrendering Emerl. Later on, when Knuckles learned about how Emerl needed Chaos Emeralds and that he grew stronger the more he fought, he vowed to help realize his full potential. Finding Emerl with Tails in Emerald Town, Knuckles trained with him until they heard the news saying that an E-121 Phi in Night Babylon, and Knuckles took Emerl with him to deal with it.

In Central City, Knuckles briefly came across Amy, only to be attacked by Chaos Gamma. After forcing Chaos Gamma to leave, Knuckles encountered Rouge, who filled him in on Chaos Gamma and learned the robot wanted revenge at Emerl. After processing this, Knuckles and Emerl continued to Night Babylon. There, they met a clerk who mistook Emerl for a Phi and called a Guard Robo. After destroying it and escaping, Knuckles lost his temper and yelled at Emerl and upset him. Apologizing for his outburst, Knuckles had Emerl wait while he went ahead. When Knuckles returned, however, Emerl was gone and he began looking for him. After several kermises with store clerks, Knuckles found Emerl with Rouge. Knuckles thought Rouge was after Emerl, but he found her innocent. Just then, they found the Phis. Knuckles and Emerl proceeded to destroy them and got their Emerald Shards before being given a Emerald Shard from Rouge as well who suggested they asked Tails about the Emerald Shards.

Heeding Rouge's advice, Knuckles returned to Tails who explained they could get a whole Chaos Emerald if the collected two more shards from the Phis. Knuckles then left with Emerl to train him and fought him to settle their score. After their battle, Dr. Eggman appeared and attacked them with a Phi, but Knuckles and Emerl defeated it, claimed its Emerald Shard and chased Eggman. Finding Eggman in Central City, Knuckles and Emerl destroyed another Phi and took its Emerald Shard. There, Knuckles acknowledged Emerl as his battle partner, before hearing Eggman say that he was heading to Gimme Shelter as he escaped.

As Knuckles got at the Gimme Shelter to catch Eggman, he was caught in Eggman's "spiky rodent trap" and Eggman revealed he tricked him. As Eggman announced plan to have Emerl absorb his Final Egg Blaster, Knuckles was left in Chaos Gamma's hands, but Emerl defeated it. Afterward, Knuckles asked Emerl to free him, but Emerl scoffed him for his lack of strength, infuriating him enough to try and break free, until Emerl shut the trap down. Heading back to Emerald Town, Knuckles had Tails put their Emerald Shards to a whole Chaos Emerald, which they gave to Emerl. As Tails wondered what happened, Knuckles asked Emerl to keep it a secret that he got tricked by Eggman. Regardless, Emerl still told Sonic and Tails, making Knuckles explode with anger.

Later on, Knuckles met Emerl again, who had come to fight him so he could fight Shadow, where he was still defeated. Later, when Eggman revealed his newest Death Egg and its Final Egg Blaster, Knuckles met up with Sonic, Tails and Emerl at Holy Summit, where he revealed that Chaos had returned, a sign of danger. As Emerl went to the Death Egg to stop Eggman, Knuckles and the others watched Emerl through a monitor.

When Eggman was defeated, however, Eggman fired the Final Egg Blaster, destroying some stars, causing Emerl to revert to his original destructive programming. However, Eggman could not control Emerl as excepted, and Emerl prepared to fire the Final Egg Blaster at earth. Knuckles then urged Sonic on as he went to the Death Egg to stop Emerl with the Master Emerald. When that failed, Sonic had no choice but to destroy Emerl. Once the deed was done, the world was saved, but everyone mourned Emerl's death.

Sonic Rush
In Sonic Rush, Knuckles was walking around on his own when he met Cream and her new friend Blaze the Cat. As he was introduced, Knuckles got angry when Cream mentioned his shortcomings but then noticed that Blaze held a Sol Emerald. Sensing that its power was similar to Chaos Energy and thus a Chaos Emerald, Knuckles advised Blaze that she gave it to Sonic for safekeeping. Blaze, however, denied his claim of having a Chaos Emerald and tried to leave, but Knuckles thought she was lying and tried to chase after her. During the chase, however, he was buried under a pile of rocks by Blaze.

Eventually, Knuckles pulled himself out of the rocks and met Sonic and Tails. Knuckles then told them how Blaze got him stuck there and took off to punch some things to went his anger, inadvertently opening a path blocked by rocks. Following that, Knuckles searched for Blaze to get some payback and eventually found her with Cream and Amy, but was held back by Amy while Cream and Blaze escaped.

In the aftermath of Sonic and Blaze's final battles with Dr. Eggman and Dr. Eggman Nega, Knuckles joined up with the others in celebration, where he warned Sonic that Amy was coming.

A while afterwards, Knuckles, along with Sonic, Tails, Amy and Cream, came to Blaze's aid when Eggman and Eggman Nega drained all her Sol Emeralds of their power to conquer both Sonic's dimension and the Sol Dimension. With Knuckles and the others supporting her, Blaze recharged the Sol Emeralds, becoming Burning Blaze, and joined up with Super Sonic, and together, they defeated the doctors and saved their worlds.

Sonic Riders
In Sonic Riders, Team Sonic arrived in Future City as they searched for a Chaos Emerald, until the Babylon Rogues appeared. When Tails read that they had the Emerald, Knuckles aided Sonic in intercepting the Rogues and knocked Storm off his Type-S though Storm still escaped. Knuckles and Tails then followed Sonic when he chased after Jet and found him knocked down while the Babylon Rogues escaped.

The next day, the team saw Dr. Eggman on the local monitors, announcing the EX World Grand Prix and that the entry fee for the contestants was a Chaos Emerald, with the winner getting to claim all seven. Seeing that the participants Dr. Eggman had found were the Babylon Rogues, Knuckles and the team decided to enter the competition.

After the qualifications rounds, Knuckles was with his team when they met Amy, who had also signed up for the tournament. After then hearing Tails explain the legends about the Babylon Rogues and Babylon Garden, Knuckles wondered how Extreme Gears worked, but found Tails' explanation too confusing. Just then, Wave came by and mocked Tails' Blue Star (and places a bomb on it), much Knuckles' annoyance. Shortly after though, Knuckles and the others hurried out to next race.

After the race, Knuckles was walking through Egg Factory when he bumped into Storm. Recognizing him, Knuckles wanted to settle the score between them. When Knuckles and Storm heard that the next race was about to start, however, they decided to settle their dispute with a race, which Knuckles won.

Before the semifinals, Knuckles and Tails watched Sonic practice his Extreme Gear techniques, until Jet appeared and mocked Sonic before taking his leave. Knuckles and his team eventually got to the finals, which Jet won after Wave sabotaged Sonic's Blue Star. They then witnessed Jet claim and use the seven Chaos Emeralds in tandem with the Key to Babylon Garden to reveal Babylon Garden itself, with the intention of claiming its treasure. Eggman, however, stole the key so that he could take the treasure for himself, believing it to be technology that he could use to conquer the world, and Knuckles and Tails followed Sonic as they headed out to stop Eggman.

Using the Tornado 2, Knuckles and Tails got to Babylon Garden, while Sonic took off on the midway to chase Eggman. There, they met Wave and Storm, and Knuckles and Storm got ready to fight, but had to stop when a flock of E-10000s attacked. Chasing after Wave and Storm, Knuckles and Tails got to Sonic's location as Sonic stopped Eggman and returned the Key to Babylon Garden to the Rogues. Knuckles and the others were then about to leave when Amy arrived and chased furiously after Sonic for attacking Eggman while he held her hostage. They heard a heard a roar and decided to check it out. Arriving inside Babylon Garden, Knuckles and the group saw the Babylon Rogues had awoken the Babylon Guardian and were forced to fight it.

After beating the Babylon Guardian, the group found the Treasure of Babylon, which was revealed to be a Magic Carpet, much to the disappointment of Eggman. With the whole ordeal over, Team Sonic and the Babylon Rogues went their separate ways, until they met again.

Sonic Riders: Zero Gravity
In Sonic Riders: Zero Gravity, a few months after the EX World Grand Prix, Knuckles was driving with Sonic and Tails through Monopole with a mysterious meteorite Tails had found the other night. On their way to Megalo Station, however, Knuckles and the others were attacked by SCR-HD and a group of SCR-GP, a part of a currently global robot rampage who were after the meteorite. In the insuring chase, the group crashed and fell out a 300-story building, though Knuckles and Tails saved themselves by flying while Sonic was saved by the meteorite which could manipulate gravity.

After that, Knuckles and the group tried to hide from the robots, where they met Amy, who was being chased by the robots because she had a meteorite similar to theirs. The group then decided to go to MeteorTech, who created the robots, for answers. There, Knuckles and the gang were discovered by security, but the Babylon Rogues arrived and Jet repelled the security robots with another meteorite. As the Babylon Rogues demanded their meteorites, called the Arks of the Cosmos, Knuckles was ready to fight, but had to wait when more robots showed up.

Arriving in the control room, the group were surprised to find Dr. Eggman, who owned of MeteoTech, though Eggman claimed to have no part in the global robot rampage. However, when Eggman recognized Sonic's Ark of the Cosmos, Knuckles threatened the doctor to tell them what he knew. Eggman then revealed that MeteoTech’s computer was powered by one of the Arks of the Cosmos and that the robot leader, SCR-HD, which also had an Ark of the Cosmos, sought them out for reasons unknown. The group then noticed Amy was gone and saw her being chased by SCR-HD and Storm on a computer screen, and Team Sonic left to save her.

When they found Amy, Knuckles and the others learned that SCR-HD had suddenly blown up and Storm had taken its Ark of the Cosmos. However, Tails deduced that they had to remove the Ark of the Cosmos in MeteoTech’s mother computer to stop the rampaging robots. As they tried to figure where the mother computer could be, Amy remembered a place Storm mentioned with info on the Arks of the Cosmos, which Knuckles recognized it as Gigan Rocks and personally lead the group there.

Arriving at Gigan Rocks, Knuckles translated the ancient scripts there and they learned that the Arks of the Cosmos were ancient power units for Babylon Garden. After then seeing the Babylon Rogues chase after Eggman above them, Knuckles translated some more inscriptions, which helped the group figure out the location of the MeteoTech’s computer mother. When they arrived there, Knuckles and the others found the Crimson Tower and the Babylon Rogues, who revealed that Eggman had stolen their Arks of the Cosmos. Understanding that Eggman planned to use the Arks of the Cosmos to control all the world's robots and conquer the world, Knuckles and the others raced against the Babylon Rogues to Eggman.

At the end of race, Eggman was stopped and the robot rampage came to an end. After Babylon Garden appeared due to all Arks of the Cosmos being present and handing over their Arks of the Cosmos, Knuckles, Sonic and Tails were about to leave when SCR-HD appeared and took all five Arks of the Cosmos to Babylon Garden. This transformed Babylon Garden into Astral Babylon, forming a black hole that threatened to consume the planet. Knuckles, Tails and the Babylon Rogues then followed Sonic to Astral Babylon to disconnect the engine where they faced Master Core: ABIS and defeated it, saving the world.

Later, Knuckles, Sonic, Amy and Tails returned to Monopole, where Tails told Knuckles and the rest of how the Arks of the Cosmos made the robots to go amok. Knuckles and then others then saw Jet flying by, who challenged Sonic to a new race, which Sonic accepted.

Sonic Free Riders
In Sonic Free Riders, Knuckles, Sonic and Tails signed up to compete in the second World Grand Prix hosted by Dr. Eggman for the sake of the competition rather than the prizes. As they were interviewed by Omochao before the competition, Knuckles was itchy to begin.

During the first round, Team Heroes faced Team Rose, who Knuckles hardly considered threating. Additional, he was annoyed by Amy berating of Sonic for not going easy. Though Team Heroes eventually beat Team Rose, Knuckles insisted they should not let their victory go to their heads.

For their next race, Team Heroes faced Team Dark. When Knuckles went up against E-10000B, however, he heard the robot making clicking sounds and moving around funny. After the race, Knuckles blamed E-10000B for foul play, but no proofs of his claims could be found. Regardless, Team Heroes still beat Team Dark.

Having advanced to the finals, Team Heroes met went up against Team Babylon, with Knuckles aggressively ready to face them for the championship. Over the course of the team face-off, Knuckles supposed both his team and mocked Team Babylon as their victory slipped away. After defeating Team Babylon, even when the opposing team was given a second chance due to mechanical trouble, Knuckles was asked for comments and said that that he had a good time since he managed to shut Jet up.

As the tournament progressed, Team Heroes had their own fair share of losses, while Knuckles remaining seriously dedicated to the competition and his team. At the end of the tournament, Knuckles and the other teams went to the awards ceremony to collect their prizes but Eggman made all of the competitors race his "ultimate Gear-jockey robot". After the race, Eggman revealed that he used the World Grand Prix to get the riders' racing data with his E-10000 robots to create the ultimate Extreme Gear which he could use for his own agenda, which Knuckles knew confirmed his suspicion about E-10000E. Eggman then challenged Knuckles and the others to a race, but lost. As Knuckles mocked Eggman for his defeat, Metal Sonic revealed himself as the one controlling E-10000B and passing fake data to Eggman, while taking the real data himself in an effort to beat Sonic in Extreme Gear riding.

Knuckles and the others following watched as Metal Sonic challenged Sonic to a race, in which Sonic defeated his robot copy. Afterwards, as the World Grand prix came to a close and everyone began to leave, Knuckles blamed Eggman for all the trouble they had to face during the tournament.

Sonic the Hedgehog (2006)
In Sonic the Hedgehog (2006), Knuckles saw Dr. Eggman on the outskirts of Soleanna and received a message from the doctor, who told him to give it to Sonic. Telling Tails he wanted to see Sonic, Knuckles awaited Sonic's arrival until he got there and gave him the message. From it, the trio learned that Eggman demanded Sonic's Chaos Emerald in exchange for the return of Princess Elise.

Despite being certain it was a trap, Knuckles, Sonic and Tails went to White Acropolis. When Sonic handed over the Chaos Emerald, however Eggman send them to an apocalyptic future with a time machine. There, they met Shadow and Rouge. The group then decided to work together to get home by finding enough Chaos Emeralds for a Chaos Control powerful enough for time travel.

While searching for the Chaos Emeralds, Knuckles, Sonic and Tails briefly saw Silver and Blaze talking with Mephiles before they went back in time. The group then learned from their database that Elise would die in the Egg Carrier's future crash-landing. Locating a Chaos Emerald in Flame Core, Sonic his friends met up with Rouge and Shadow and went to the central volcano, where found the Emerald only for Iblis to attack them. After defeating Iblis, Sonic and Shadow use their two Chaos Emeralds to create a time-space rift, which Knuckles, Tails and Sonic used to return to the present. After that Knuckles helped find information on Elise's whereabouts. Later on, Knuckles helped Sonic through Aquatic Base to save Elise from her imminent death onboard the Egg Carrier.

Later on, Knuckles passed through Castle Town with Tails and Amy when they were suddenly caught in a spatial distortion created by Solaris and send to End of the World, where they met Shadow, Silver, Rouge, E-123 Omega and Eggman. There, they also found Elise and Sonic, and Knuckles saw to his shock that Sonic was dead, having been killed as a part of Mephiles' plan to remake Solaris. As Solaris prepared to consume time itself, Knuckles opted to destroy him, but it was deemed impossible due to Solaris' temporal omnipresence and Sonic's passing. When Elise sensed that Sonic's soul was still among them however, Knuckles and the others collected the seven Chaos Emeralds to revive Sonic. After Elise revive Sonic as Super Sonic, Knuckles stood behind and supported Super Sonic, Super Shadow and Super Silver as they defeated Solaris before they all were engulfed in light. When Sonic and Elise then ensured Solaris never came to exist, time was reverted, resulting in the events and memories of the adventure being erased and Knuckles to be returned to where he was prior to the events.

Sonic Rivals
In Sonic Rivals, Knuckles was guarding the Master Emerald when it suddenly disappeared. His search for the Master Emerald eventually took him to Onyx Island where he saw who he believed was Dr. Eggman, but was really Dr. Eggman Nega disguised as Dr. Eggman (Knuckles however, does not realize this throughout the game) with Sonic, and he suspected the doctor was behind the theft. Confronting Eggman Nega, the doctor showed he had turned the Master Emerald into a card with his special camera. Meanwhile, Sonic asked Eggman Nega where Tails and Amy's where, and Eggman Nega showed that he had turned them into cards too. As Eggman Nega escaped, Knuckles raced Sonic to the doctor.

After they found Eggman Nega, the doctor attacked in the Egg Turtle which they defeated. After the doctor escaped, Knuckles met Shadow, who also looked for Eggman Nega. However, when Shadow criticized him for letting the doctor escape, Knuckles raced Shadow to find Eggman Nega first. When they reached Eggman Nega, Knuckles demanded the Master Emerald back, but the doctor attacked them in the Egg Falcon, which they defeated.

After the battle, Knuckles was teleport to another area by Eggman Nega with the Master Emerald. There, he met Silver, who had come to bring Eggman Nega back to the future. After answering Silver's questions, Knuckles started asking him, but Silver did not answer, provoking Knuckles to chased after him. Eventually, Knuckles found Eggman Nega and asked how he stole the Master Emerald only to be told that Onyx Island was Angel Island before he was attack by Metal Sonic. After beating Metal Sonic, Knuckles pondered about how Onyx Island could be Angel Island when he met Shadow. As Shadow berated him for letting the doctor get away again, Knuckles raced Shadow to Eggman Nega.

When Knuckles found Eggman Nega, the doctor explained that Onyx Island was Angel Island from the future, before he attacked with the Egg Lynx. After defeating the machine, Knuckles tried to make sense of what Eggman Nega said, when he met Sonic and Tails. Not wanting Sonic to outdo him as he seemed to know where the doctor was, Knuckles raced Sonic to Eggman Nega.

When they found Eggman Nega, Knuckles demanded a full explanation. Eggman Nega then revealed that the Master Emerald disappeared because he turned it into a card in the future, which due to the Master Emerald's properties made it disappear in all time frames, and that he then used it to transport the Angel Island in the future to the present as Onyx Island. Deeming Eggman Nega responsible for all this, Knuckles defeated both the Egg Kong and Metal Sonic. Frustrated at his constant defeats, Eggman Nega told Knuckles that he now planned to turn the world into a card and escaped. Sonic and Tails then showed up in the Tornado when they heading to Eggman Nega’s base, and Knuckles teamed up with them to stop Eggman Nega. On their way through Eggman Nega’s base, Knuckles and Sonic met Shadow and Silver and they all put aside their differences to stop Eggman Nega.

At the center of the base, Knuckles and the others found a large spaceship with Eggman Nega’s special camera equipped on that he planned to use to turn the world into a card. Knuckles then noticed that Eggman Nega planned to fuel the device with the Master Emerald's card and some other cards, but the four rivals destroyed the spaceship as it took off, thus foiling Eggman Nega’s plan. With the Master Emerald back, Knuckles planned to use it to send Onyx Island back to the future where it belonged, and as well to look for the other treasures Eggman Nega had trapped in cards.

Sonic Rivals 2
In Sonic Rivals 2, Knuckles looked for the Master Emerald when it went missing again. Arriving on an island, Knuckles suspected that Dr. Eggman was behind the theft. Knuckles then met Rouge, who offered to take him to Eggman if he helped her find the Chaos Emeralds, which he agreed to. Knuckles then saw Sonic and Tails, who were also looking for Eggman and asked Sonic if he had seen Eggman. Sonic, however, insisted on getting to Eggman first, so Knuckles competed with Sonic to find Eggman.

Knuckles and the others eventually found Dr. Eggman, who was really Eggman Nega masquerading as Dr. Eggman (Knuckles does not realize this throughout the game). Knuckles demanded the Master Emerald back, but the doctor played innocent and attacked in his Egg Liner. Knuckles and Rouge then followed Eggman Nega to Sunset Forest Zone, where Rouge thought the doctor had to have an Emerald Detector to locate the Chaos Emeralds and Master Emerald, and they decided to find this device. On his own, Knuckles met Shadow who insisted on keep them from the Emeralds once he told him story, forcing him to fight him.

Knuckles and Rouge eventually found Eggman Nega with Shadow and Metal Sonic. As Knuckles demanded Eggman's Emerald Detector, the doctor attacked in the Egg Dealer. After defeating it, Knuckles and Rouge got the Emerald Detector, which picked up a signal. As Knuckles searched the area in Neon Palace Zone, he met Silver, who wanted some Chao. After looking for Rings for the Emerald Detector, Knuckles asked Silver of why he sought Chao, but thought he was crazy when he heard it was to save the world, and they ended up fighting. Later on, Knuckles and Rouge found Eggman Nega with Silver and Espio, and the doctor attacked in the Egg Dealer, but the group defeated it.

Arriving in Frontier Canyon Zone, Knuckles and Rouge lost track of Eggman Nega. The Emerald Detector soon found more Emeralds, but Knuckles was frustrated that none of them were the Master Emerald. Knuckles then saw Shadow and Metal Sonic nearby and followed them, with Knuckles chasing Metal Sonic after him after hearing Eggman's voice come from the robot. Shortly after, Knuckles met Rouge, who explained that Eggman Nega sought to bring forth the Ifrit to destroy the world. Just then, Eggman Nega attacked them in the Egg Bull, but Knuckles and Rouge defeated it despite inference from Shadow and Metal Sonic.

At Mystic Haunt Zone, Knuckles was convinced by Rouge that Eggman was here. While looking, Knuckles met Espio and asked him if he had seen Eggman or Shadow, hoping they had the Master Emerald, but was dismissed. Soon after, Knuckles met Metal Sonic and fought him so he would bring him to Eggman Nega. Afterwards, Knuckles found Eggman Nega and Shadow and demanded the Master Emerald back. As Eggman revealed that he used Rouge to collect all the Chaos Emeralds for opening the portal to the Ifrit's dimension, and Silver then arrived, Knuckles had enough and fought the Egg Phantom.

After the battle, Knuckles saw that the portal to the Ifrit's dimension was opening, despite Rouge only having six Chaos Emeralds (with the seventh unknown to them being inside Metal Sonic). Intending to stop the Ifrit, Knuckles dragged Rouge with him into the Ifrit's dimension. After entering, Knuckles lost track of Rouge and began to look for her, and soon after found the Ifrit, who had taken control of Rouge. With no choice, Knuckles fought both Rouge and the Ifrit. Despite Knuckles occasionally falling prey to the creature's mind control, the two defeated the Ifrit, thus preventing it from leaving its world and got back to their home dimension before the portal closed.

After checking up on Rouge, Knuckles was annoyed the Master Emerald was still lost, but then discovered that it had been inside the Emerald Detector all along. As Knuckles was praise by Rouge for his heroism, he saw Rouge leave with the Master Emerald and he chased after her.

Sonic Chronicles: The Dark Brotherhood
In the beginning of Sonic Chronicles: The Dark Brotherhood, Knuckles, Sonic, Tails and Amy faced Dr. Eggman on the Egg Carrier, and successfully made the flying vessel crash into Metropolis while Eggman was presumed dead in the crash.

Some time later, Knuckles learned that six of the Chaos Emeralds had been stolen by a group dubbed the Marauders. Intending to stop them, Knuckles came to Tails and had him set up a trap for the Marauders by using the last Chaos Emerald. When the Marauders appeared, however, they jammed the trap and turned on Knuckles who was overwhelmed by numbers and defeated by their leader, Shade, for then to be taken with them as they escaped with the Chaos Emerald.

Locked up in their hideout, Knuckles attempted to break out, when he met Sonic, Tails and their friends, who had come to rescue him. When Knuckles decided to head back to Angel Island to protect the Master Emerald from the Marauders, they discovered that the island was gone. Suspecting that Eggman was working with the Marauders, the group began looked for the doctor using Tails' Eggman Detector. With a Pattern Generator made from Eggman Devices they found, the team located Eggman. However, the doctor claimed that he was against the Marauders as well, and that he had also been reformed, willing to help Knuckles and the others fight the Marauders by leading them into Metropolis where the Marauders had drawn Angel Island to with the Chaos Emeralds, which they accepted.

On their way there, Knuckles and the others met Shade and her lackeys, and Knuckles discovered that Shade and the Marauders were a group of echidnas called the Nocturnus Clan, exiled to the Twilight Cage in ancient times. After defeating them, Shade blocked their way to Metropolis, but Knuckles and the others found a way around it. Meanwhile, Knuckles was torn to finally meet others of his kind, but was forced to fight them. Regardless, Knuckles was joined by Sonic and his party when he went to Angel Island to secure the Master Emerald, while Tails and Eggman made a weapon against the Nocturnus Clan.

By hijacking an airship and with some help from Tails' team, Sonic and his group got to Angel Island where they met the Nocturnus Clan’s leader, Imperator Ix, who sought to rule the world. Ix unleashed his soldiers on them, but Knuckles and Sonic held them off until Tails and Eggman came and deployed their weapon, which dispatched the soldiers. United, the team fought Ix until the techno wizard blew him and the others away, even Shade, but Knuckles saved Shade. Ix then stole the Master Emerald and used it to create a wormhole into Knuckles' dimension so that the Nocturnus Clan could conquer it, while Angel Island fell from the sky. The team then came up with the plan of going after Ix into the Twilight Cage and reclaim the Emeralds, and Shade joined Sonic’s team to stop Ix’s plan, having realized the evil nature of her leader.

Having constructed the Blue Cyclone, Knuckles and the group entered the Twilight Cage, while Eggman stayed behind. Inside the Twilight Cage, Knuckles and his team got five of the Chaos Emeralds back and got the alliance of the alien races residing there. When they planned to invade Nocturne to get the last Emeralds, Knuckles remained reluctant to fight Ix and instead hoped to return the echidnas to Earth peacefully so that he would not be alone anymore. With the assistance of the alien races, Knuckles and the others got to Nocturne. Once there, Knuckles got the team split into two, with him and Shade leading their group and Sonic and Tails leading the other, to find the last two Chaos Emeralds, which Charyb and Scylla possessed. Knuckles, meanwhile, planned to redeem Ix before Sonic could get to him.

Soon after, Knuckles and his team were almost defeated by Gizoid Centurions, but were saved by Sonic and Tails. Knuckles and his team then found and defeated Scylla and got his Chaos Emerald, before helping Sonic's group defeat Charyb. Afterwards, Knuckles and his team were teleported to Ix, who tried to persuade Knuckles to join him. Realizing Ix was unredeemable, Knuckles declined and stood by his duty while vowing to help the Nocturnus Clan his own way before fighting Ix. Sonic then arrived and ensured the defeat of Ix while Knuckles reclaimed the Master Emerald. With his final defeat, Ix started to close the wormhole out of the Twilight Cage, but Knuckles and the others got through it just in time. When they returned home however, Knuckles and the others saw that much time had passed, thus allowing Eggman to rebuild his forces, which they faced upon exit from the Twilight Cage.

Sonic Colors
In the Nintendo DS version of Sonic Colors, Knuckles got a letter from supposedly Dr. Eggman which made him go to Dr. Eggman's Incredible Interstellar Amusement Park, though later on he eventually realized when he got there that he had been tricked.

Here, Knuckles met Orbot and Cubot and fought them, thinking they were behind the letter. However, he was distracted when he saw Sonic and Tails coming allowing Orbot and Cubot to get away. As Sonic and Tails began questioning him, Knuckles tried to cover up that he had been tricked and challenged Sonic to a mission. After he lost, Knuckles moped over his defeated, but still denied he had been tricked. In the scenario where the mission is cleared with an S Rank, Knuckles took his defeat more sportily.

Later, Knuckles met Rouge and suspected she was after the Master Emerald again. As Knuckles continued to argue with Rouge, Sonic and Tails arrived to try to break up their argument, but Knuckles stopped them while still denying that he had been tricked when Rouge brought it up. When Knuckles then noticed Rouge knew something about his letter, he learned from her that she wrote the letter, leaving him feeling very humiliated.

Sonic Generations
In the console/PC version of Sonic Generations, Knuckles attended and helped prepare Sonic's surprise birthday party. As the party began, however, the Time Eater suddenly appeared, and Knuckles was sucked into one of the Time Eater's Time Holes and ended up in the White Space, where he was turned into a statue due to the Time Eater's effects.

Eventually, Knuckles was returned to normal by Classic Sonic (Sonic's past self) and Modern Sonic (Sonic's present self). When Classic and Modern Sonic later confronted the Time Eater, which was revealed to be controlled by Modern Eggman and Classic Eggman, Knuckles arrived at the battle with the others and cheered on both Sonics, allowing them both to transform into Super Sonic. When the Sonics defeated the Time Eater, Knuckles and the others were sent back to the present, where Knuckles admitted to Sonic that he was not half-bad, only to be knocked into a tree by Amy for thinking so little of him. Continuing the celebration where it left off, Knuckles later waved goodbye to Classic Sonic and Classic Tails when they returned to their own time.

Sonic Lost World
In Sonic Lost World, Knuckles remained behind with Amy to look after some animals while Sonic and Tails went out to free the other animals Dr. Eggman had captured. When Amy contacted Sonic, who revealed they had only got one capsule of animals back, Knuckles boasted that he could have done better before he was pushed away.

When the Deadly Six took control of Eggman's Extractor and began draining the Life Energy out of Earth, Knuckles observed the planet's energy being taken away. Eventually, Knuckles was drained of his energy to the point where his death seemed imminent. Fortunately, he and everyone else were saved when Sonic and Tails got the Extractor to return the stolen energy. When Sonic and Tails returned, Knuckles boasted he would have finished it sooner, but accepted the outcome nonetheless, before seeing Sonic try to take a nap.

Sonic the Hedgehog 2
Knuckles does not actually appear in the original version of Sonic the Hedgehog 2, but he does appear in the 2013 remastered version for the iOS/Android versions' good ending if the player collects all 7 Chaos Emeralds, where he is seen hiding in the bushes as Dr. Eggman is throwing a temper tantrum at his defeat in the end screen similar to his appearance on the cover of Sonic the Hedgehog 3. In addition, plugging Sonic the Hedgehog 2 into Sonic and Knuckles will unlock a version of the former game where Knuckles is the main character.

Sonic and the Secret Rings
In Sonic and the Secret Rings, Knuckles took on the persona of Sinbad the Sailor from Arabian Nights. He is sought out by Sonic and Shahra as they need his help to stop the Ifrit Golem, one of the Erazor Djinn monsters. After freeing him from his prison, he tells them they can use his water blue World Ring to weaken the Ifrit Golem, but they had to take it back of the band of pirates who stole it from him. He is last seen following Sonic on his last adventures through the Arabian Nights as Sonic sought out a way to return home. He also appeared as a playable character in Party Mode.

Sonic and the Black Knight
Knuckles is in Sonic and the Black Knight. He is portrayed as Sir Gawain of the Knights of the Round Table, and uses the Galatine, two swords. He is guarding the cave when Sonic approaches him. Gawain thinks he is stealing the Dragon's treasure and attacks. After being defeated, he attempts suicide to avenge his honor since he failed his king's orders, but Sonic asks him if there is more to being a Knight than serving a king. He later helps with stopping Merlina's corruption of the Kingdom. Other than looking like Knuckles, Sir Gawain seems quite gullible like Knuckles originally was, and defends the dragon's treasure, a parallel to Knuckles because he defends the Master Emerald. His Soul Surge is Gail Meteor.

Mario & Sonic Series
Knuckles also appears in the game Mario and Sonic at the Winter Olympic Games. In the game he is a power-type character. His main rival is Wario. Knuckles signature move is the Screw Driver on the Wii and Spiral Uppercut for the DS version.

In Mario and Sonic at the olympic games, he has five missions and boss fight with Wario in Dream boxing. Missions are:
 * Throw three times increasing your distance with each throw in Hammer throw
 * Finish in 2nd place in 400m
 * Perform GREAT or PERFECT in all aspects of 10m platform
 * Perform 5 successful smashes and win in table tennis
 * Perform one combo within 30 seconds in Dream basketball

Sega Superstars Tennis
He also makes a cameo appearance in Sega Superstars Tennis in the Green Hill court, and in both Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS (in the unlockable Green Hill Zone stage where he, Tails, and Silver run through the shuttle loop in the background).

Sonic &amp; Sega All-Stars Racing
Knuckles appears as a playable character in the racing game Sonic &amp; Sega All-Stars Racing. His All-Star Move is Emerald Power, which allows Knuckles to glide above the track and unleash an earthquake that stuns all opponents.

In the console versions, Knuckles is playable from the start, but in the DS and iOS versions, the user needs to pay 500,000 SEGA miles to play as him.

Sonic & All-Stars Racing Transformed
He returns as a racer once again in Sonic & All-Stars Racing Transformed, though he's changed his quad for a strange backward trike influenced by himself in this game.

Personality
Knuckles is independent, wild, tough and a loner by nature. Like how Sonic embodies the wind, Knuckles embodies the mountain; aloof, unmovable and anchored to his duty. Due to having lived in seclusion for most of his life, Knuckles is a rather antisocial and reclusive individual. As such, he cares very little about what others thinks, which makes him bluntly honest, straight-forward and speaks his mind confidently. Being the last of his kind, Knuckles walks his very own path and doesn't stick around often.

Knuckles is fiercely loyal to his homeland, and does whatever is in his power to protect it. He prefers to stay close to the island's current emerald shrine to keep a watchful eye over everything on his home. Despite this devotion, Knuckles is willing to leave his duty whenever his help is needed, or when he feels the Master Emerald and Angel Island will be safe. Though Knuckles has found other lifestyles appealing, he will never trade away his duties as he is far too devoted to his role as guardian. When not performing his duties, Knuckles prefers spending his time practicing his fighting skills, going treasure hunting or hang out with his friends.

Knuckles is most of the time very serious, earnest and usually likes to be by himself. He is likewise stubborn, headstrong and inflexible, prefering to do things his own way, which causes him to clash with others. Regardless, he is very strong-willed, seldom wavering in his determination and will not give up on his goals once he has set them.

Though he is cool and determined in battle, Knuckles has an extremely short temper and is difficult to talk to or reason with when he is angry. Though his wild temper has often been known to get him into trouble, Knuckles has also learned to use it to his advantage by channeling it into his fighting skills.

Despite his tough facade, Knuckles is heroic, brave and kind-hearted, being devoted to helping others in trouble, even when those people are his enemies. He is likewise a loyal and caring friend, who is always willing to help his friends out in tight situations and will do anything to protect them.

Having been living much of his life in isolation, Knuckles grew up believing in honesty, and holds a strong and steadfast belief that there is good in everyone, which always lets him give people second chances. Because of his lack of social ingenuity, however, it makes him very naive, extremely gullible and easily misled, which has given him a history of being tricked by Eggman. Over time, however, Knuckles has gotten better about this and is more suspicious concerning Eggman's trickery. Once he finds out he has been tricked, Knuckles can get quite angered, but quickly regains enough of his composure to immediately start working towards a resolution. Despite this, Knuckles also has a friendly side, especially towards his friends, or when he's in a good mood. He is also very selfless, risking his life to save anyone, and shows empathy for people, even if they are a villain or enemy.

Though not dull-witted, Knuckles often chooses force to be the solution, pushing himself through obstacles while focusing on his goal and ignoring other factors along the way. When in his right element, however, Knuckles can be quite clever and sneaky, such as setting several successful traps for Sonic and Tails on Angel Island when they first arrived.

Knuckles is said to be shy around women, which makes him act awkwardly around girls like Amy, Blaze and Rouge. Because of his secluded lifestyle on Angel Island, Knuckles feels very uncomfortable in industrialized or crowded cities and places, and being around hi-tech objects or gadgets (mostly because he's not inclined).

Knuckles seems to have matured somewhat in Sonic Generations. While he still displays some brooding, headstrong and stubborn additude, he is shown being better to acknowledge his shortcomings and displays more personal restraint and better social interaction.

Strength
Knuckles' trademark ability is his immense amounts of superhuman physical strength, so vast that he can shatter boulders, punch holes through thick steel and lift objects several times his own size and weight. Knuckles' strength is believed to be equal to Sonic's mundane speed (Mach 1), which would make him able to lift and press 100 metric tons, making him physically stronger than all other characters in the series. Knuckles' strength seems to lie in his upper body, particularly in his arms and fists, the later of which are noted to be as hard as rock.

Another testament to his brute strength is that he can punch or throw objects through air with such force that he can ignite fire, and create fissures, tremors and even small volcanic eruptions by punching the ground. He can even strike with such force that it causes the friction in the air to create explosions with enormous power.

Physical Abilities
Like most other character in the series, Knuckles is shown to be very fast on his feet, being able to run at remarkable, near-superhuman speeds, though he still not quite as fast as Sonic, Tails or Shadow. Additionally, his high speed does not seem to extend to his upper body, and he has been noted for having slow movements in combat. Over time, Knuckles began to lose some of his speed, but also gain a lot more power.

Knuckles also possess near-maximized physical endurance to match his strength, and is capable of taking as much major punishment as he is able to deal out, even being able to survive a bomb exploding right in front of him. Knuckles is as well strong enough to hold out against an army of robots without rest.

Unlike Sonic, Knuckles is a very experienced swimmer, due to his interest of being a treasure hunter, and can swim to incredible depths and with both great speed and skill.

Knuckles is also shown to have sharp reflexes and acrobatic skills, being able to do special tricks and movements while in mid-air, though he is not nearly as acrobatic as Sonic or Shadow are, nor can he jump very high. To make up for his lack of agility, however, Knuckles possesses a wide range of movement abilities. By stretching his arms and legs outwards while airborne, Knuckles can catch the wind under his dreadlock-like spines, allowing him to glide long distances through mid-air and can do so with great control over his movements. Also, by using the spikes on his fists, Knuckles can attach himself to walls and climb up any kind of surface with ease, no matter the material.

Knuckles is also a proficient burrower, able to dig into any wall or floor and excels at tunneling through subterranean regions with great speed.

Knuckles also the uncanny ability to sense the Chaos Energy of the Chaos Emeralds from a distance, or objects similar to them, such as the Sol Emeralds. Like Sonic and Shadow, Knuckles can also harness the power of the Chaos Emeralds to empower himself.

Combat Skills
Being the guardian of the Master Emerald, Knuckles is a very powerful fighter. He is skilled in a number of martial arts, focusing on hand-to-hand combat, and is capable of taking on even the most powerful of opponents without rest, such as when he was able to take down several of the military trained Nocturnus Clan soldiers. Even more so, he has been able to fight Sonic the Hedgehog to a standstill on several occasions. Also, in Sonic Chronicles: The Dark Brotherhood, Tails noted that anyone to beat Knuckles in a fight must be very powerful, a testament of his fighting abilities.

Fighting Style
When in battle, Knuckles makes most use of his powerful arms and fists to take on his foes, with his specialty lying in punching moves where he uses his spiked fists to their fullest (there are some cases where it resembles a form of boxing). In terms of fighting style, Knuckles' focuses specially on power, using strong and powerful punches, such as powerpacked jabs or piercing uppercuts, to deal damaging blows to his opponents. Once he catches an opponent in his combos, he keep them trapped by keeping up his strikes, not allowing his opponents a chance to counterattack. For stronger strikes, Knuckles tend to build up momentum with his fists by swinging them around, before hitting his opponent with full force. In his Major Eruption move in Sonic Battle, Knuckles takes advantage of his burrowing abilities, hiding underground and hitting opponents with an uppercut as he leaps out when his opponent least expects it.

Despite being a powerhouse in close combat, as stated by Sonic, most of Knuckles' fighting moves are slow and easy to read, making Knuckles more vulnerable to those who give themselves time to read his moves.

Techniques and Moves
Knuckles' various moves and techniques revolves around his trademark Punch Attack, where he attacks his opponents with various punching combos, including surrounding his fists with fire. His Spiral Upper allows him to strike foes above him with a spinning uppercut, and his Drill Claw sends him spiraling down on his foes from above. Similar to those, he also has his Screwdriver which allows him to home directly at his enemies. For wider impacts, Knuckles can use his Hammer Punch or Knuckle Slam to create wide tremors or explosions that effect everything within their effect range.

Knuckles has also been shown being able to use Sonic's trademark Spin Attack and Spin Dash to curl himself up and spin into a spiky ball when in motion that can damage, destroy or mow down many obstacles or foes or even burrow underground. He does, however, not use these moves or their variants, such as the Homing Attack, as often as Sonic and Shadow do.

When gliding, Knuckles can also use his Grinding/Gliding Knuckles Attack in conjunction with his movements, using the spikes on his fists to damage any foes he comes into contact with during his descend. With his Maximum Heat Knuckles Attack, Knuckles glides through air at high speeds, destroying any foes within his attack range.

Miscellaneous Skills
Knuckles is an expert treasure hunter, which is shown during his several hunts for Emerald Shards, and can be considered one of the best treasure hunters in the world, if not the best. While not exactly highly intelligent, Knuckles is well-versed in ancient cultures, ruins and legends, and is very knowledgeable on the subject, such as when he was able to translate the ancient texts at Gigan Rocks with little effort.

Knuckles is also one of the few who knows how to access and utilize the powers of the Master Emerald, allowing him to harness the powerful emerald's various abilities.

Knuckles has been shown to possess some mystical abilities of his own, possibly due to his close connection to the Master Emerald, such as in Sonic Battle, where Knuckles displays some limited geokinetic abilities, such as harnessing elemental earth energies to protect or heal himself, or calling forth meteor-like rocks from above to strike his opponents, which is described as "supernatural control of earth". In Sonic & SEGA All-Stars Racing and it's sequel, Knuckles can harness the Master Emerald's power in his All-Star Move Emerald Power to fly and increase his strength.

Knuckles has proven himself to be a skilled Extreme Gear in the Sonic Riders series, having shown himself a worthy competitor against many of the world's best Extreme Gear riders. To best put his skills in perspective, Knuckles was able to beat Storm the Albatross in a race, who is a part of the world's best Extreme Gear rider team, the Babylon Rogues. When riding his Extreme Gear at high speeds, Knuckles can bash his way through certain obstacles effortlessly, and, when someone gets near him on their Extreme Gear, he can engage in close combat with his opponents, without losing control over his Extreme Gear.

Transformations
Like Sonic and Shadow, Knuckles has the ability to power up into stronger forms of himself, usually by using Chaos Energy from the Chaos Emeralds and Super Emeralds. These transformations grants Knuckles overall improved physical abilities, such as greater strength and speed, and abilities he did not have access to before.

Super Knuckles
In Sonic & Knuckles and Sonic the Hedgehog 3 & Knuckles, with the seven Chaos Emeralds, Knuckles is able to become Super Knuckles. In this mode, Knuckles glows pink, as opposed to most other character's golden glow. When Knuckles is in his Super State, he gains invincibility and all his powers and natural abilities are enhanced up to their full limit. Super Knuckles is several times faster and more powerful, and can climb walls twice as fast and fly. He however needs rings to maintain this transformation.

Hyper Knuckles
In Sonic the Hedgehog 3 & Knuckles, Knuckles can also transform into an extended version of Super Knuckles, called Hyper Knuckles with the seven Super Emeralds. Unlike Hyper Sonic, who blinks multicolored, Knuckles blinks between bright and dark shades of Red and Pink. In this form Knuckles is faster and stronger than Super Knuckles and he can destroy all on-screen enemies by gliding into a wall, causing the stage to shake. He also have the ability to fly at a fast speed without staying in the air long enough to reach the speed when he is in normal form. Hyper Knuckles is also incapable of drowning. Like Hyper Sonic, Hyper Knuckles has an after image effect when moving.

Sonic the Hedgehog
Sonic is Knuckles' good friend and rival. They have known each other for a long time, but their relationship seems to be somewhat complicated. The two do not understand their differences and they often cause fights, Sonic being cool and cheeky and Knuckles being tough and serious. The two of them were initially enemies, due to Eggman's trickery, but after Knuckles realized the truth, he and Sonic came to have a more friendly relationship. Despite this, however, Knuckles still held an inhospitable attitude towards Sonic, due to their different points of view and natures. This is hinted in Sonic Heroes, however that this might stem from the fact that Knuckles is jealous of Sonic's independent nature and freedom, finding it enviable, though he would never admit it.

Knuckles is often tricked by Dr. Eggman into believing that Sonic is the bad guy. That causes them to get into fights and Sonic teases Knuckles whenever this happens, in which Knuckles does not take it very well. However, since then he has gotten better with this and is more aware of Dr. Eggman's plans. With Sonic's speed paralleling Knuckles' strength in every way, their fights are always climatic.

The rivalry has all but disappeared in some continuities and in others it is a sort of game between the two, actually serving as the plot for the game Sonic Rivals, where Dr. Eggman (really Eggman Nega in disguise) captures Tails and the Master Emerald and turns them into cards. Knuckles tells Sonic that he must get to Eggman first and save the Master Emerald, so Sonic decides that they should race each other, which Knuckles agrees on.

Over time, Knuckles' relationship with Sonic has improved and he has come to see Sonic as both a rival and one of his best friends (the other being Tails) and help each other in many situations. The two show teamwork in battle as seen in Sonic Heroes and in Sonic the Hedgehog (2006).

In Sonic Generations, it is shown that Knuckles is actually impressed by Sonic and has belief in his abilities, but does not directly want to admit it. This is shown when Knuckles responded, "Thanks for the help, not that I needed it!" after Modern Sonic saves Knuckles and also when Knuckles told Sonic when he was not "half bad" after fixing the time, beating Time Eater and saving his friends. If Classic Sonic saves him, then he compliments Sonic by responding, "Thanks Sonic, you did a good job back there", which implies that he will sometimes admit, although he also asked if Sonic gained weight.

Dr. Eggman
Knuckles is constantly tricked by Dr. Eggman. In Sonic 3, Eggman had tricked him saying that Sonic's the enemy who is stealing the Chaos Emeralds, and because of Knuckles' simplicity he had believed Eggman and played various tricks on Sonic as well as fighting him. Knuckles has also been tricked by Eggman in Sonic Advance 2. Knuckles was tricked by Eggman again in the TV show Sonic X, but as the games pass by, Knuckles has stopped falling for Eggman's tricks, as mentioned in the guide for Sonic Riders: Zero Gravity. Knuckles has also shown a rough attitude towards him in the Sonic Rivals series even once stating that he will not believe anything he says a twist to his former attitude against him and something even Eggman is taken aback from.

Rouge the Bat
Rouge the Bat is Knuckles' rival. Knuckles and Rouge have been fighting over the Master Emerald ever since the two met. Rouge was designed to be Knuckles' compatibility just like how Shadow was designed to be Sonic's compatibility when it comes to basic rivalry and skills.

In Sonic Adventure 2, when Knuckles purposely shatters the Master Emerald to save it from Dr. Eggman, Knuckles and Rouge both go looking for its pieces. Eventually, Knuckles has to hunt Rouge down for the remaining pieces, and the two have their final confrontation at the level, Meteor Herd. But during their fight, he saves her life instead after she slips on a narrow beam and was about to fall into a burning pit of lava. After the rescue, Rouge and Knuckles share a long moment gazing at each other, before Rouge snatches her hand away and retorts with ungratefulness and teasing. In the end, Rouge gives him the remaining pieces of the Master Emerald and stubbornly complains that, "They stink like echidnas do!". Knuckles gathers the shards to complete the Emerald and glances over to her, muttering, "I'm sorry if I hurt you...", and runs off. Before the scene fades out, Rouge gives a thoughtful smile over her shoulder before exiting.

In Sonic Heroes, at the end of Team Dark's story, Rouge commented that she would go look for the Master Emerald, "since that irritating echidna is here." However, in the last scene, she went to Knuckles and coquettishly hinted about going to look for someone else's treasure. Knuckles smiles and says "She never gives up, does she?"

In Sonic Chronicles: The Dark Brotherhood, codex states that, "there's a sort of unstated connection between Rouge and Knuckles that neither are overly willing to explore." Rouge even admits that Knuckles is cute but just not her type during the game.

In Sonic Rivals 2, the two are teamed up. Rouge's reason for this is because she had a mysterious client who told her that if she found all the Emeralds, she would be rewarded. She teamed up with Knuckles in search for the identity of her client. They fight the Ifrit to get back to normal depending on which side you play.

In Sonic the Hedgehog (2006), Rouge joins up with Knuckles to collect the 7 Chaos Emeralds to bring Sonic back to life.

In Sonic Colors, Knuckles explains to Rouge that he is at Starlight Carnival because he received an invitation from Dr. Eggman, but proving that he did not get tricked. Rouge tells him that the invitation was written by her, causing Knuckles to burst in anger.

In Sonic Generations, Knuckles and Rouge oddly seem to be friendly to each other at the party, as they are seen setting the table, eating, smiling and talking to each other.

Friends/Allies

 * Sonic the Hedgehog (Best Friend & Rival)
 * Miles "Tails" Prower (Best Friend)
 * Amy Rose
 * Cream the Rabbit
 * Cheese
 * Big the Cat
 * The Chaotix
 * Vector the Crocodile
 * Espio the Chameleon
 * Charmy Bee
 * Mighty the Armadillo
 * Blaze the Cat
 * Silver the Hedgehog
 * Shadow the Hedgehog
 * Rouge the Bat (also rival)
 * E-123 Omega
 * Shade the Echidna

Rivals

 * Wario (in the Mario & Sonic series)
 * Rouge the Bat (friendly rival)
 * Blaze the Cat (formerly)
 * Sonic the Hedgehog (friendly rival)
 * Storm the Albatross (rival in strength)

Enemies

 * Doctor Eggman
 * Orbot
 * Cubot
 * Metal Sonic
 * Doctor Eggman Nega
 * Fang the Sniper
 * Pir'Oth Ix
 * Black Doom
 * Black Arms

Sonic Underground
In Sonic Underground, Knuckles is the lone guardian of the Chaos Emerald on the Floating Island. While he was a kid, he met Queen Aleena who told him that he would be the first ally of her children Sonic, Manic and Sonia to join them in the war against Dr. Robotnik.

Years later, Knuckles met Sleet and Dingo who tricked him into believing that Sonic, Manic and Sonia where thieves after his island's Chaos Emerald. When Sonic, Manic and Sonia arrived on the Floating Island to find their mother, Knuckles attacked them until Sonic saved his life. After cleared up the misunderstanding, Knuckles and the hedgehog siblings teamed up to reclaim the Chaos Emerald Sleet and Dingo had stolen before the island fell from sky, and they became the allies Aleena wanted. When Dr. Robotnik found another Chaos Emerald, Knuckles aided Sonic, Manic and Sonia in reclaiming and containing the Chaos Emerald when it ran rampant.

Sonic X
In the anime series Sonic X, Knuckles originally lived on a parallel version of Earth in another dimension, where he guards the Master Emerald. He takes his job seriously and has a fearsome temper with a "chip on his shoulder". During one of the battles with Dr. Eggman, an accidental large-scale Chaos Control send Knuckles, Sonic, Dr. Eggman, and their friends to the human world. Upon stranding in this world, Knuckles' only desire was to get back home quickly. Preferring to do things his own way, Knuckles spend most of his initial time on Earth traveling alone rather than joining up with Sonic and their friend, though he would occasionally come to their aid to fight Eggman and as well befriend other characters.

When Angel Island was later transported to Earth after he failed to work together with Eggman to bring them back home, Knuckles returned to guarding the Master Emerald while helping Sonic with other major threats. Eventually though, Knuckles and everyone from his world returned home after learning their presence was threating to freeze time.

Six months after returning home, Knuckles was persuaded to join Sonic and his friends in their fight against Metarex, an alien race of cyborgs that was a threat to the safety of the entire galaxy, when they needed him and the Master Emerald to power the Blue Typhoon. During the final showdown, Knuckles was forced to sacrifice the Master Emerald to defeat the Metarex's leader, Dark Oak. After defeating the Metarex, Knuckles returned home to look over the Master Emerald until its power could return naturally.

Sonic the Hedgehog: The Movie
In Sonic the Hedgehog: The Movie, Knuckles is a traveling treasure hunter who roams the Land of Darkness and a long-time friend of Sonic the Hedgehog and Tails.

When Sonic and Tails came to the Land of Darkness to stop the Robot Generator from destroying Planet Freedom, Knuckles came to the duo aid when they came under attack by Metal Robotnik and helped destroying the metallic menace. When it turned out that the Robot Generator was a trap made by Dr. Robotnik to complete Hyper Metal Sonic, Knuckles helped Sonic, Tails and their allies in stopping Metal and Robotnik from destroying the world.

Sonic Boom
Knuckles has appeared as one of the main characters in the new CGI animated TV series, Sonic Boom, which has aired in Fall 2014, and its video games.

Archie Comics
In the Sonic the Hedgehog comic book series and its spin-offs published by Archie Comics, Knuckles is the eighteenth Guardian of Angel Island, and a member of the Brotherhood of Guardians. Born to Locke and Lara-Le, Knuckles' DNA was indirectly tampered with and his unhatched egg was irradiated with Chaos Emerald radiation by Locke so he had a chance of facing a horrible threat in the future which Locke had seen in a vision. The result was a child with barbs on his knuckles and incredible powers–a "living Chaos Emerald."

Knuckles was raised by in Guardian tradition by his father in the wilds on Angel Island and then left to fend for himself at ten. Knuckles learned self-reliance while his forefathers monitored his process, sometimes lending him a hidden hand. Despite the Brotherhood's neutrality, Knuckles joined the First Robotnik War after a meeting with Sonic the Hedgehog and later the Second Robotnik War. The mysteries around his life began to unravel when the effects of the Ultimate Annihilator returned both the Dark Legion and the city of Echidnaopolis to Angel island. Knuckles was expose to a family and heritage he knew he had.

As his prowess grew in facing new challenges, Knuckles' Chaos power grew out of control, transforming him into Chaos Knuckles, a form with god-like power, but had little to no control. The transformation culminated when Knuckles was forced to fight Mammoth Mogul to save his distant ancestor and old foe Dimitri, where he released all his power to stop Mogul and died in the process. Knuckles joined the Chaos Force to a degree even the Ancient Walkers had reached. However, with his cosmic awareness, he sensed the Xorda Invastion of Mobius. Using his unlimited power, Knuckles returned to life - but sacrificed his "living Chaos Emerald" quality, leaving him weak and powerless until the Master Emerald's energies restored his powers.

His Chaos Force connection was later abused Dr. Finitevus who used dark magic to transform Knuckles into Enerjak. As Enerjak, Knuckles made sweeping changes to Angel Island and the world. He was restored, but at the cost of Locke's life, making him withdrawn to almost everyone. He endured further losses when he later lost almost all the echidnas on Mobius to Thrash the Tasmanian Devil.

Sonic the Comic
In Sonic the Comic, 8,000 years ago, Knuckles was the leader of the echidna armies under Pochacamac, fighting the Drakon Empire. Presumably by being placed in suspended animation, Knuckles survived to the present day, but with no memories of his earlier life. Seemingly the only echidna left in this era, Knuckles came to live on the Floating Island where he alone guarded the Chaos Emeralds. In addition to a near obsession of protecting his island, Knuckles is greatly affected by the uncertainty of the fate of his own people.

When Dr. Robotnik and his Death Egg II crashed on the Floating Island, Knuckles was tricked by the doctor into believing Sonic the Hedgehog sought to steal the island's Chaos Emeralds. Knuckles thus allowed Robotnik to rebuild the Death Egg II on the island, and assisted him in fighting Sonic and stealing Sonic's own six Chaos Emeralds so they could be combined with Knuckles' into one set of Emeralds. Knuckles, however, was skeptical enough to conceal that he had the missing Grey Emerald, so when Robotnik revealed his betrayal and tried to absorb the Emeralds' power, Knuckles used the Grey Emerald to defeat him.

From that point on, Knuckles worked as an ally to the Freedom Fighters in the battles with Robotnik. When Dr. Zachary appeared, Knuckles stopped him from destroying Mobius, but then had to spend the next period undoing the subsequent damage to the Floating Island, which culminated as he returned home to stop Robotnik and Zachary from turning the Emerald Hill refugees into an organic computer. After Robotnik had been overthrown, Knuckles came to help Sonic and his friends' with the following threats, such as when Robotnik tried to force Mobius into environmental collapse and when Chaos was unleashed.

Reception
The character has received generally positive attention. According to IGN, fans "seemed legitimately happy" with the addition of the character of Knuckles, who was popular enough to get marquee billing in Sonic & Knuckles, but the writer felt that characters that came after him were going "overboard." IGN's Colin Moriarty singled out the introduction of both Knuckles and Tails as when the series became "iffy" and listed them and all other characters in the series, sans Sonic and Robotnik, as being 2nd most in need to "die" on his top 10 list. In contrast, he was listed as the best Sonic character by Official Nintendo Magazine based on the impact he brought to the Sonic games in which he first appeared.

Complex listed Knuckles as their eleventh most wanted character in the next Super Smash Bros. game. In another article, Complex regarded Knuckles as a better character than Sonic, and praised his gliding and climbing abilities, stating "even if his levels were a little more challenging than Sonic's, the thrill of being able to explore certain parts of levels that the blue-colored hero could not was worth it". Game Rant include Knuckles on their list of "Top 10 Third-Party Characters that Could Appear in the New Super Smash Bros.", commenting "This punch-drunk brawler knows how to serve up a buffet of knuckle sandwiches, and there’s no question that he’s one of the most fitting characters to occupy a spot on the roster".

Mega Zone's review of Knuckles' Chaotix praised the introduction of a new protagonist, whom it deemed "rougher [and] tougher" in comparison to the "spineless" Sonic. Mean Machines Sega called Knuckles' powers "impressive" and the character overall more useful and promising than Tails.[80] Sega Magazine stated that Knuckles "looks cooler" than Sonic, comparing him to Spider-Man, and suggested he be given his own game. Sega Magazine later called him "groovy" and "ace", concluding that they "love him."

Quotes

 * "Still got it!" - Winning in Sonic Rivals 2.
 * "Ah finally..." - Restoring the Master Emerald in Sonic Adventure 2.
 * "As far back as I can remember, I've been living here on this dark island... Always guarding the Master Emerald from anything that could harm it. I don't know why I was given this job... Why it was my fate... Destined to be here... forever!" - Knuckles thinking about his life at the beginning of his story in Sonic Adventure.
 * "The servers are the seven Chaos. Chaos is power. Power is enriched by the heart. The controller is the one who unifies the chaos. Only you can do this. STOP THE CHAOS EMERALDS!" - Knuckles pleading with the Master Emerald to neutralize the power of the Chaos Emeralds in Sonic Adventure 2.
 * "It's closer..." - When the Emerald Radar turns red.
 * "I found 'em!" - When finding the three pieces of the Master Emerald in Sonic Adventure 2.
 * "Yeah, I feel good!" - After getting a B Rank.
 * "What do you think you're doing Shadow!?" - Knuckles when Shadow destroys a G.U.N. robot or soldier in Shadow the Hedgehog.
 * "Me? My fists are my weapons of choice." - Knuckles saying that he would rather use his fists than a gun in Shadow the Hedgehog.
 * "Hey good going." - Knuckles when Shadow defeats a Black Arms alien in Shadow the Hedgehog.
 * "Hand it over Eggman. I'm losing my patience." - Knuckles demanding Eggman to give him the Emerald Detector in Sonic Rivals 2.
 * "No time for games..." - Knuckles when he is about to use a special attack in the 2-Player mode of Sonic Adventure 2.
 * "Get down!" - Knuckles after unleashing the Hammer Punch special attack in the 2-Player mode of Sonic Adventure 2.
 * "Take this!" - Knuckles after unleashing the Thunder Arrow special attack in the 2-Player mode of Sonic Adventure 2.
 * "Take that!" - Knuckles after unleashing the Power Flash special attack in the 2-Player mode of Sonic Adventure 2.
 * "Look who's calling who a thief." - While Eggman was stealing the Master Emerald and Rouge called him a thief in Sonic Adventure 2
 * "I will protect the Master Emerald." - When starting a multiplayer stage in Sonic Adventure 2.
 * "That's a good one, YOUR Emerald. Talking to you is a waste of time!" - Knuckles before his second fight with Rouge in Sonic Adventure 2
 * "Just enough to pass." - Getting an E Rank in Sonic Heroes.
 * "What a wild ride." - Going in circles in Sonic Heroes.
 * "I'm so ready..." - Knuckles while standing still for a while in Sonic Heroes.
 * "Time for a Knuckles sandwich!" - Knuckles taunting the opposing team in the minigames of 2P Battle mode of Sonic Heroes.
 * "Whew, that was pretty tough." - Knuckles when defeating Metal Overlord in Sonic Heroes
 * "Well if I can't convince them, then I'll just let my fist do the talking!" - Being the last one still on the field when facing Team Rose in Sonic Heroes
 * "No way!" - When Knuckles tries to dig on something like metal or steel in Sonic Adventure
 * "Did she say red mutt?" - After Wave calls him a red mutt before leaving with Storm on the Babylon Garden in Sonic Riders
 * "Stone Fists! - After wining a fight in Sonic Battle
 * "It's not me! Blame Sonic!" - When talking to Rouge in the Japanese version of Sonic Battle
 * "I feel some strange energy..." - While walking around in the Space Colony ARK right before Sonic Chaos Controls in front of him in Sonic Adventure 2.
 * "As much as I hate to admit it, I think Tails is right about this." - Knuckles after hearing Tails' plan to defeat Perfect Chaos by helping Sonic go Super in Sonic Adventure
 * "We've no time to waste. We've got to defeat it now!" - Knuckles' frustration with Solaris ready to consume time itself in Sonic the Hedgehog (2006).
 * "I'll probably be on this floating island forever. Guarding the Master Emerald, again. I may not know the whole story behind this. But perhaps it's better that way. I am at peace once more." - Knuckles thinking once again about his role as Guardian of the Master Emerald in the ending of his story in Sonic Adventure
 * "I'm unstoppable!" - When Knuckles speeds up in Mario & Sonic at the Olympic Winter Games on the Wii
 * "Don't get in my way!" - When starting a race in Sonic Riders: Zero Gravity
 * "Anytime! Babylon Rouges!" - When finding the Babylon Rouges in MeteoTech
 * "Let's go... Yah!!" - About to perform a Gravity Dive in Sonic Riders: Zero Gravity
 * "It's a pretty famous ruin among us treasure hunters." - Knuckles explaining the Gigan Rocks to Sonic, Tails, and Amy in Sonic Riders: Zero Gravity
 * "Stooop! I get it, okay?! It just floats and that's good enough﻿ for me!" - Knuckles asking Tails to stop explaining how an Extreme Gear floats in Sonic Riders
 * "I sure don't wanna fall off." - Knuckles when the player turns the camera too much in Sonic Adventure and Sonic Adventure DX.
 * "A trap!? What have you done Eggman!?" - Knuckles confronting Dr. Eggman at the top of Crimson Tower in Sonic Riders: Zero Gravity.
 * "Outta my way!" - When attacking in Sonic Riders and Sonic Riders: Zero Gravity.
 * "It's over..." - Knuckles after dying in Sonic Adventure 2.
 * "Yeah! This is perfect!" - After getting an A Rank.
 * "I am one with the Master Emerald" - Starting a treasure hunt on 2-Player mode of Sonic Adventure 2
 * "My emerald, my destiny" - Getting a piece of the emerald on 2-Player mode of Sonic Adventure.
 * "If that's what you thought, you should've given me them in the first place." Knuckles after Rouge gives him the pieces of the Master Emerald in Sonic Adventure 2.
 * "I didn't use all my strength!" when getting a D-rank in Sonic Heroes or getting 2 stars in Sonic and the Black Knight.
 * "Stop attacking the good guys!" Knuckles when Shadow destroys a G.U.N robot or soldier in Shadow the Hedgehog.
 * "I must...protect...the Master Emerald..." - Knuckles, after losing to Rouge in their first, and only, battle on the ARK, in Sonic Adventure 2.
 * "Alien Scum!" - Knuckles when Shadow defeats a Black Arms alien in Shadow the Hedgehog.
 * "Damn! A dead end! Looks like we have to take our chances with the tornado!" - Knuckles, after arriving to a tornado in Glyphic Canyon in Shadow the Hedgehog.
 * "Hmph. I'm just warming up!" - Sonic Heroes.
 * "Thanks, Sonic! You did a good job back there! Hey, did you gain weight?" - Knuckles after Classic Sonic rescues him at Sky Sanctuary in Sonic Generations.
 * "Thanks for the help. Not that I needed it! But it's good to have my sanctuary back." - Knuckles after Modern Sonic rescues him at Sky Sanctuary in Sonic Generations.
 * "I'll handle the treasure hunting!" - Knuckles before the Sky Sanctuary mission with Modern Sonic begins.
 * "Come on Sonic, smack him!" - Knuckles cheering Sonic to keep going in Sonic Generations.
 * "Help! We're being sucked in!" - Knuckles when he gets sucked into the tornado in Shadow the Hedgehog.
 * "Yeah, that's what I'm talkin' about!" - When Knuckles wins a world tour event in Sonic and All-Stars Racing Transformed.
 * "How long are they going to make us wait? All this pent up energy is making me itch." - Knuckles in Sonic Free Riders.

Solo

 * Knuckles has his own percussion theme in Sonic 3 & Knuckles.
 * In Sonic Adventure, Knuckles' theme song is called "Unknown From M.E." It is a mix of hip-hop, jazz, pop, and R&B. This song was performed by Marlon Saunders and Dred Foxx. This theme also appeared in Sonic and the Black Knight when Sir Gawain appears and when the Medal Of Gawain item is equipped.
 * In Sonic Adventure 2, Knuckles' theme song is also known as "Unknown From M.E." but has a faster pace and a greater focus on pure rap, and performed by Marlon Saunders and Hunnid-P.

Shared

 * In Sonic Heroes, Knuckles' team, Team Sonic, theme tune is called "We Can," and actively mentions him in the lines; 'And Knuckles by our side, makes this a safer ride.'
 * In Sonic Riders, Knuckles' theme, shared with Sonic and Tails, is an instrumental called "High Flying Groove."

Trivia

 * According to the Sonic 3 manual, Knuckles' favorite food is grapes. This is referenced many times in the games.
 * In Sonic Generations, once Sky Sanctuary and Knuckles are restored, grapes can be seen growing on a tree behind Knuckles. This is an Easter Egg for Knuckles as grapes are his favorite food.
 * Strangely, in Sonic 3, Sonic & Knuckles, and Sonic 3 & Knuckles, the cutscene Knuckles is slightly pinker than the playable Knuckles. This is due to the palettes conflicting with the HUD items, the playable Knuckles was able to be perfected so this would not happen.
 * Knuckles has been tricked six times all together in the TV shows he stars in. Twice in Sonic Underground, and four times in Sonic X.
 * In Sonic 3 & Knuckles, finishing the game with only the Chaos Emeralds leaves a picture of the character's Super State on the Game Select screen. If the game is completed with Knuckles, an image of Super Knuckles is shown. In this image, he appears to be the same color as Knuckles, but with a bright purple aura.
 * In the Mega Drive games he is playable in, the letters K.T.E. (Knuckles the Echidna) are by his life icon, instead of "Knuckles" because the name display could not support more than than five letters, like on "Sonic" and "Tails".
 * Due to space limitations, in Sonic Drift 2, Knuckles' name is spelled "Knucles".
 * Knuckles' eye color has varied in the Sonic series, changing from blue to purple. In Sonic Battle, he is actually portrayed with both eye colors (blue for the fighting and purple for the cutscenes.)
 * He and Shadow were originally confirmed to appear in Sonic Unleashed, though neither were seen nor mentioned in the released game.
 * Knuckles' music was one of the reasons for the "Mild Lyrics" warning in Sonic Adventure 2. "Unknown From M.E.", "Deeper" and "Kick the Rock!" were among them.
 * Knuckles and Amy are the only 2 Sonic characters who appeared to have "aged"; Knuckles going from 15 to 16, and Amy going from 8 to 12.
 * Knuckles, along with Sonic and Dr. Eggman are the only characters whose Japanese voice actors have voiced their character in all Sonic games since Sonic Adventure.
 * Knuckles is the only playable character in Sonic '06 who does not finish a level/boss/town mission. Despite this, Knuckles does have a victory pose. This can be seen if the player glitches the levels to the end with Knuckles, the victory pose is almost identical to his Sonic Adventure 2 victory pose.
 * During multiplayer on Sonic Heroes, the white crest symbol on Knuckles' chest will disappear while he is taunting the opponent.
 * In Sonic Rivals and Sonic Rivals 2, the player can unlock an Eggman costume for Knuckles.
 * Knuckles' socks and shoes have been miscolored multiple times:
 * In Sonic the Hedgehog 3, Sonic Triple Trouble and Sonic & Knuckles, Knuckles' socks were colored yellow during cutscenes as it interfered with the HUD palette. The playable version of Knuckles in has green socks however.
 * In Sonic Drift 2 and Sonic 3D Blast, Knuckles' socks were colored blue.
 * in Sonic R, Knuckles' shoes instead resemble Tails' white-tipped shoes, save for the metal tops and green socks. In still art however, his shoes are correctly colored, but the yellow stripe covers the back too.
 * In a lot of the 2D games, the crest on Knuckles' chest is colored peach. But in later games, it's colored white.
 * Knuckles is the only character in the franchise with purple eyes.
 * One of Knuckles' nicknames is "Knuckle," as stated in the Japanese manual of Sonic 3.
 * In Sonic Battle, Sonic once calls Knuckles a "spiky-headed mole". This is a pun on how echidnas and moles have the same burrowing prowess. It is also be a play on the Japanese term for echidna, which literally translates as "needle-mole".
 * He is also mistakenly referred to as a mole in the Sonic OVA movie.
 * If the player pauses at the right moment, in Sonic the Hedgehog 3 or Sonic and Knuckles when the sign is twirling in the air, the Knuckles color will be blue instead of red.
 * Super Sonic is invincible to any damage, but somehow Knuckles knocked the Chaos Emeralds out of him in Sonic 3 & Knuckles. This indicates that Knuckles is powerful enough to knock him out of Super State.
 * In Sonic 3 and Knuckles, if one glitches Knuckles into Sonic's part of Marble Garden Zone Act 2, Tails will still fly him up so he can defeat Dr. Robotnik. It is the only time this can be done without a cheat.
 * In Sonic Colors, Knuckles is the only one of the "Side Quest" characters to have five poses. All the others have four.
 * Knuckles' crescent-shaped symbol on his body was originally going to be the NIKE logo on him as part of a short-lived sponsorship deal.