Knuckles the Echidna

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 echidna and the current guardian of the Master Emerald, a powerful ancient relic which is his solemn duty to protect from anyone seeking 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 super 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 walls. 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 entirely devoted to his duty, spending most of his time on Angel Island protecting the Master Emerald, and rarely cares for anything that is of no importance. 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 faithful and good-hearted hero. He is also one of Sonic's oldest friends and rivals.

Concept and creation
Knuckles was 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 initially meant to speak with a Jamaican accent.

Knuckles was created by developer Takashi Yuda, who never intended him to be any more than a "supporting character." Knuckles was introduced in Sonic the Hedgehog 3 as an "intimidator" because of his powerful abilities. He was given a headlining role in the next game, Sonic & Knuckles.

Appearance
Knuckles is an anthropomorphic echidna with red fur that covers most of his body, peach skin on his muzzle, a white crescent-shaped patch of fur on his chest, and purple eyes. He also has seven dreadlock-like spines on his head and a medium-sized tail.

For attire, Knuckles wears red and yellow shoes, each with green cuffs and a grey, sextuple-bolted plate on top. He also wears white, mitten-like gloves with sock-like cuffs and two spiked knuckles on each hand. Both his gloves are quite large.

Personality
Knuckles is independent, wild, tough, and a loner by nature. Like how Sonic embodies the wind, Knuckles embodies the mountain; stern, 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 think, which makes him bluntly honest, straight-forward, and somewhat egotistical.

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 at 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 hanging out with his friends.

Knuckles is usually solemn, stoic, collected, and usually likes to be by himself. He is likewise stubborn, headstrong, and, inflexible, preferring to do things his 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. While he is cool and determined in battle, Knuckles has an extremely short and wild temper and is hard to reason with when he is angry. Though his 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 being a silent loner, Knuckles is heroic, brave, kind-hearted, and selfless, risking his life to save anyone or get them out of trouble, and shows empathy for people, even if they are a villain or enemy. 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. When not angered, Knuckles is pretty laid-back and never cracks under pressure. He can also be very understanding on the sly and does not take kindly to people who disrespect or hurt his friends, or innocents in any way.

Having been living much of his life in isolation, Knuckles grew up believing in honesty and holds a firm 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, incredibly gullible, fast about forgiving people and easily misled, which has given him a history of being tricked by Eggman. This has made Knuckles aggressive and suspicious towards anyone he deems questionable. 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 start working towards a resolution immediately.

Though not dull-witted, Knuckles is often prone to rash and ill-advised actions. While not above picking complex strategies, Knuckles often chooses force to be the solution, pushing himself through obstacles while focusing on his goal and ignoring other factors along the way. Similarly, he can also be quite reckless when panicking about the Master Emerald, such being especially evident during the Space Colony ARK incident, where he ended up fighting Sonic for the controls of the Space Shuttle and causing it to crash land as well as abandoning his allies out of a panic due to the Master Emerald shards being lost to space from a collision with a meteor forcing the cargo bay open. When in his right element however, Knuckles can be quite clever, sharp-witted and sneaky, such as setting several successful traps for Sonic and Tails on Angel Island when they first arrived. He is also capable of learning from his mistakes. Knuckles has also proven himself to have a high degree of leadership skills, most noticeably during his time as the commander of the Resistance. He is noted to be very charismatic with inspirational speeches, and he has a flair of daring plans that provided the Resistance with a much-needed offensive during the War to Take Back the Planet. However, for all his skills as a leader, Knuckles is still easily distracted and prefers to be out on the battlefield rather than in the command center.

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 lightened up somewhat in Sonic Generations. While he still displays some brooding, headstrong and stubborn attitude, he is shown being better to acknowledge his shortcomings and displays more personal restraint and better social interaction.

Powers and abilities
Being the guardian of the Master Emerald, Knuckles is a very powerful fighter. He is a master 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 took 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 who can beat Knuckles in a fight must be very powerful, a testament to his fighting abilities.

Knuckles' trademark ability is his immense superhuman strength, which is so vast that he can pulverize massive boulders, punch through solid steel, and lift objects several times his size and weight with ease. By comparison, Knuckles' strength is stated to equal Sonic's speed; considering Sonic's measured footspeed, which range between Mach 1-5, it would mean that Knuckles is capable of lifting 100-500 metric tons. This makes Knuckles one of the physically strongest characters in the series. Knuckles' strength seems to lie in his upper body, particularly in his arms and fists, the latter of which are noted to be as hard as rocks. Another testament to Knuckles' strength is that by punching the ground, he can create fissures, widespread tremors, and even small volcanic eruptions. Additionally, he can punch with his fists or throw objects through the air with such force that they ignite from friction. He can even launch punches with such force that they cause air molecules to split and create explosions of enormous power.

Knuckles is shown to possess the ability to run at breakneck speeds, enough to let him keep up with both Sonic and Tails' running speed. He is even able to run fast enough to create afterimages of himself. Even so, he is not quite as fast as Sonic at his maximum speed, as Knuckles is noted to run fairly slow by comparison. Additionally, while Knuckles is capable of executing rapid punches in quick succession within a split-second, he has been noted to have slow movements in combat.

Knuckles possesses near-maximized physical endurance and durability to match his astounding strength. He can thus take just as much punishment as he can dish out and has achieved numerous feats of impressive durability. These include surviving a bomb exploding right in front of him through sheer toughness, and going through atmospheric reentry and then land on the ground unharmed. Also, despite the force of the impacts Knuckles' fists receive when punching at high forces, he is never phased by the recoil, regardless of what he hits or how hard he is hitting. Knuckles additionally has enough stamina to hold out against an army of enemies without rest.

Unlike Sonic, Knuckles is a very experienced swimmer. Due to his interest of being a treasure hunter, he can swim to incredible depths and with both great speed and skill. Knuckles is also a proficient burrower, able to dig into any wall or floor and excels at tunneling through subterranean regions at great speed.

Knuckles is also shown to have sharp reflexes and acrobatic skills, enough to let him do special tricks and movements while in mid-air, pull off various Spin Attack maneuvers at high speed, and grind along rails just as fast as Sonic while doing tricks and evading obstacles. Additionally, Knuckles can jump several stories into the air from a standstill position. While not being quite as acrobatic as Sonic and Shadow, Knuckles makes up for his lack of agility through his wide range of movement abilities. By stretching his arms and legs outwards while airborne, Knuckles can catch the air under his dreadlock-like spines to ride on air currents, allowing him to expertly glide long distances through mid-air. Also, by using the spikes on his fists, Knuckles can scale any kind of surface with ease.

Knuckles has the uncanny ability to sense the chaos energy of the Chaos Emeralds and the Master Emerald, or similar objects like Sol Emeralds, and can track down their "signals" which makes him a living Emerald Detector. Like Sonic and Shadow, Knuckles can also harness the power of the Chaos Emeralds to empower himself.

When in battle, Knuckles makes 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 for some devastating effects. In terms of fighting style, Knuckles' focuses specifically on power, using robust and forceful punches, such as power-packed jabs or piercing uppercuts to deal damaging blows to his opponents. Once he catches an opponent in his combos, he will 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, 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 the fastest characters who can read his moves and rapidly counterattack.

Knuckles can also perform the Spin Attack, where he curls tightly into a concussive ball or cutting disk, while in locomotion to damage, mow down, or burrow through obstacles and foes, and any substance if given enough speed. Using the Spin Jump, Knuckles can leap into the air and curl in a spinning ball to deal damage to anything he lands on. The Spin Dash lets him shoot himself as an acceleration roll at high speeds to break barriers or mow down enemies. The Homing Attack allows Knuckles to jump and home in on an enemy to attack.

Knuckles is also an expert treasure hunter with infallible instincts (which is referred to as his treasure sense ), 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. He can sense the presence of treasure nearby and is even able to pick up its scent and sniff his way to it. 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 has been shown to possess some mystical abilities of his own. In addition to summoning lightning bolts. He displays some limited geokinetic abilities, such as harnessing elemental earth energies to protect or heal himself, or calling forth meteors from above, which is described as "supernatural control of earth". Knuckles is also one of the few who knows how to access and utilize the Master Emerald, allowing him to tap into the gem's powers to utilize its different properties or empower himself.

Knuckles has proven himself to be a skilled Extreme Gear rider, having proven 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 regarded as a legendary wind Master. When riding his Extreme Gear, Knuckles can bash his way through obstacles effortlessly and engage in close combat with his fellow racers, without losing control. With his Extreme Gear skills, Knuckles can even enhance his physical abilities.

When it comes down to it, Knuckles can show very competent leadership skills. This was primarily demonstrated during the War to Take Back the Planet where he was able to lead the Resistance for several months against the Eggman Empire and even come up with war strategies of his own. As seen during Dodon Pa's Grand Prix, Knuckles also has excellent skills when it comes to driving and racing in racecars like the Land Breaker.

Super Knuckles
With the seven Chaos Emeralds, Knuckles is able to attain a Super State known as Super Knuckles. In this state, all of Knuckles' abilities far surpass his normal ones. In addition, he is able to fly and is virtually invulnerable. However, this transformation consumes a lot of energy and requires Rings to be maintained.

Hyper Knuckles
In Sonic the Hedgehog 3 & Knuckles, Knuckles can transform into an extended version of Super Knuckles, called Hyper Knuckles, with the seven Super Emeralds. This form basically shares the same abilities and powers as Super Knuckles but on an even higher level.

Color Powers
By harnessing different variants of Hyper-go-on from Wisps, Knuckles can use specific Color Powers to transform into a certain form, such as a drill, a laser or even a planet, each one possessing its own unique abilities. So far, Knuckles has been able to transform into the Cyan Laser, Yellow Drill, and Indigo Asteroid. However, these transformations require a steady supply of Hyper-go-on to be maintained.

Sonic the Hedgehog
Sonic the Hedgehog is Knuckles' rival and best friend. The two have known each other for quite a long time, but their relationship seems to be somewhat complicated, with Sonic being cool and cheeky and Knuckles being tough and serious. The two of them were initially enemies, due to Dr. Eggman's lies, but after Knuckles realized the truth, he befriended Sonic. Despite this, however, Knuckles still held a somewhat 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 enemy, being this a great cause for many of their confrontations. This would make them get into fights and Sonic teases Knuckles whenever this happens, in which Knuckles does not take it very well. This mostly occured in early games such as Sonic the Hedgehog 3 & Knuckles and Sonic the Hedgehog Triple Trouble, where the relationship between them wasn't clearly defined, with the two having just met each other. However, since then he has gotten better with this and has become 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 most continuities, with its prominence having diminished considerably over the years, mostly after the introduction of Shadow the Hedgehog in Sonic Adventure 2 as Sonic's arch-rival, but remains as a sort of game between the two. It actually serves as the plot for the game Sonic Rivals, where Dr. Eggman (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 agreed on.

Over time, Knuckles' relationship with Sonic has improved greatly and he has come to see Sonic as both a rival and one of his best friends (the other being Tails), helping each other in many situations. Knuckles is a vital part of Sonic's team, and the two have worked together several times, as seen in Sonic Heroes and in Sonic the Hedgehog (2006).

In Sonic Generations, Knuckles helps organize Sonic's birthday party. In this game, 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", although he also asks him if he gained weight.

In Sonic Lost World, Knuckles helps Sonic in his task to rescue the animal friends from Dr. Eggman, working separately (alongside Amy) from him and Tails. Through the game, Knuckles jokingly teases Sonic by telling him he could finish faster, although at the end of the game, he is happy to see Sonic and Tails returning from their adventure.

In Sonic Forces, Knuckles takes the position of commander of the Resistance against the Eggman Empire after the latter managed to capture Sonic and take over the world. In this game, the echidna is shown to be much friendlier towards Sonic, as he is seen worried about the hedgehog's well-being at the time of his disappearance, and is actually joyful when Rouge informs him that Sonic is actually alive. When Knuckles hears Sonic's voice in the Avatar's communicator, he expresses happiness, although he is also concerned about his friend's escape from the rebuilt Death Egg. As Sonic returns to earth, Knuckles tells his friend that seeing him back was "the best news they could have had in months".

Miles "Tails" Prower
Miles "Tails" Prower is a close friend of Knuckles, and who he has known for longer than anyone else after Sonic and Doctor Eggman.

Although they don't seem to have much of a relationship in the earlier games, when they first met, Knuckles and Tails were enemies, as Doctor Robotnik had tricked the echidna into believing Tails and Sonic were intruders seeking the Chaos Emeralds for evil purposes, though they become friends later on when Knuckles discovers that Robotnik had lied to him.

Unlike with Sonic, Knuckles does not see Tails as his rival, and generally shows a more amicable towards the fox as well, particularly compared to his interactions with Sonic and other characters, although Tails occasionally irritates Knuckles with his technobabble. Likewise, Knuckles seems to enjoy teasing Tails from time to time as well, such as when he scares Tails with the idea that they fought with Shadow's ghost just before entering Hang Castle. Despite this, Knuckles is probably Tails' best friend after Sonic, and the two have teamed up several times through the series.

Knuckles has also shown that he cares about Tails, having assured Tails he had nothing to worry about when the fox cub once grew worried about Eggman's plots in Sonic Heroes; in that same game, the two were also hanging out in the Tornado 2 at the very beginning, before reuniting with Sonic later on, and Knuckles even points out after the trio defeated the Egg Emperor at Dr. Eggman's Final Fortress that the hedgehog "wouldn't of had a chance" if "it wasn't for [them]". He similarly defended Tails after Wave the Swallow taunted Tails in Sonic Riders. In Sonic '06, Tails and Knuckles appear as Sonic's main allies during his story; the two are also seen cheering Sonic in his battle against Solaris, and celebrating together after Solaris' defeat. In Sonic Rivals, after Sonic had rescued Tails at Death Yard Zone, Knuckles (who was on a quest of his own to recover the Master Emerald), was seemingly surprised and happy to see Tails free from the card containing him at the same time; Tails later aids Knuckles and Sonic reach Eggman Nega's stronghold, the Meteor Base Zone. In Sonic Forces, both Tails and Knuckles (along with the rest of the Resistance) agree to be "friends forever", at the end of the game.

Although they are good friends, Tails and Knuckles have fought each other on a few occasions (almost always when Knuckles has been tricked by Eggman), but in the end, there are never any hard feelings between them.

Amy Rose
Amy Rose has only been seen interacting with Knuckles on rare occasions, although they seem to have an awkward, yet at the same time, friendly relationship. Although the two do not interact much (if at all) in the earlier games, they do so more often in the later installments of the series. In Sonic Heroes, the two are on opposing sides; when playing as Team Sonic, at the beginning of the battle against Team Rose, Knuckles will taunt Sonic about Amy saying, "Have you been messing with that girl's heart again Sonic?" In Sonic Rush, Amy stops Knuckles from starting a fight with Blaze. In Sonic Forces, they work together as part of the Resistance. Although they get along well in this game, Amy has to keep Knuckles in check at times, especially when Knuckles was more than willing to do the distraction at Green Hill himself, with Amy then saying that as the commander of the Resistance, he needs to stay at the Resistance HQ.

Dr. Eggman
Although at the beginning they were partners, Knuckles is the third most formidable foe the mad scientist has, after Sonic and Tails, thwarting his plans most of the time.

Knuckles is constantly tricked by Dr. Eggman as well, specially whenever Sonic's involved. In Sonic the Hedgehog 3 & Knuckles, 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. In Sonic Adventure, Eggman deceives Knuckles again, telling him that Sonic was looking for the pieces of the Master Emerald; while at first Knuckles was skeptical of Eggman's claims, he later saw Sonic holding a green Chaos Emerald, which he mistaked for the pieces he was looking for, and fought his friend, although, he later realizes he was wrong and makes peace with Sonic.

Knuckles has also been tricked by Eggman in spinoff titles such as Sonic Advance 2 and Sonic the Hedgehog Triple Trouble, but as the games pass by, Knuckles has stopped falling for Eggman's tricks, and has generally become more aware of his plans, as mentioned in the guide for Sonic Riders: Zero Gravity.

Knuckles has also shown a rough attitude towards him, particularly in later games, such as 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.

Shadow the Hedgehog
Knuckles and Shadow don't have much interaction with each other, but when they do, they are either allies or rivals. He and Knuckles started off as enemies in Sonic Adventure 2 because Shadow impersonated Sonic and had him thrown in jail at Prison Island. Towards the end of the game, they became allies when they had to save the planet from the Space Colony ARK. The first real fight between them happened in Sonic Heroes when Team Dark provoked Team Sonic into battling them, although Shadow didn't remember Knuckles or Sonic and Tails. After the fight, Knuckles jokingly mentioned that they might have fought Shadow's ghost. In Shadow the Hedgehog Knuckles appears in Glyphic Canyon, Central City, and Black Comet stages asking for Shadow's help in Hero missions. In Sonic the Hedgehog (2006) he and Shadow were loosely allies in the game, and they worked together again for a time in order to return to the present.

Shadow and Knuckles appear to have some bitter resentment towards each other as seen in Sonic Rivals when Shadow bluntly pointed out that Knuckles was useless for his shortcomings while retaining an indifferent attitude towards his challenges, and Knuckles seemed to be irritated by Shadow's presence. Knuckles seems to have a bit of a disliking towards Shadow at times, mainly because of Shadow's indecisive attitude and smug demeanor, and an example of this is seen in Sonic Free Riders when Knuckles pointed out that Shadow had a big ego in a rather annoyed tone. Overall, Knuckles and Shadow's relationship revolves around their goals.

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, they became enemies when they met because Rouge had stolen the Master Emerald from him, and she was working with Shadow and Eggman. Also, 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 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 and Knuckles were bitter allies during their mission to travel back to the present day but joined up with him to collect the seven 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. They are also friendly with each other in Sonic Forces, and Rouge holds no qualms with being a spy under Knuckles' command, even acknowledging him as "boss".

Blaze the Cat
Knuckles first met Blaze when Cream wanted Blaze to be friends with him. Knuckles was initially very friendly and cordial towards Blaze before he noticed Blaze holding a few Sol Emeralds, which he mistook for Chaos Emeralds. He therefore gave Blaze advice to give them to Sonic. Blaze got angry at Knuckles and told him that she did not have any Chaos Emeralds. Knuckles then got angry at her and accused her of lying, and then made an attempt to attack her. Blaze dodged Knuckles' attack and and knocked him out, leaving him to lie in a crevice. When Knuckles regained consciousness, he developed a loathing towards Blaze and wanted revenge. When they met once again, Knuckles nearly started a fight with Blaze, but he was stopped by Amy. Cream also convinced Blaze that Knuckles was actually a "nice guy", which made Blaze feel relieved. Soon, Knuckles let go of his grudge and befriended Blaze.

Storm the Albatross
When Knuckles and Storm the Albatross met, Knuckles punched Storm really hard while the latter was trying to commit a theft, which caused Storm to fall from his Extreme Gear. Ever since then, the two have been rivals over who is the stronger man. When Storm lost against Knuckles in the World Grand Prix, he falsely accused him of having cheated. In Sonic Riders: Zero Gravity, the two also showed a spark of anger when they saw each other again. In this encounter, Knuckles thought of Storm as a "meathead" while Storm wanted to settle the score between them, causing great tension between the two.

Silver the Hedgehog
Knuckles and Silver the Hedgehog appear to have a friendly relationship with a small rivalry between the two. Although they do not have much interaction with each other, they have had heated battles with one another occasionally. In Sonic Forces, Knuckles was the first person Silver warned about Eggman's attack, which led to the War to Take Back the Planet. In the game, Knuckles and Silver appear to be on very good terms with each other, and work very well together. In fact, Silver appeared to be one of Knuckles' most trusted lieutenants, indication that Knuckles has considerable respect for Silver.

Friends/allies

 * Sonic the Hedgehog (best friend and rival)
 * Miles "Tails" Prower (best friend and teammate)
 * Amy Rose
 * Cream the Rabbit
 * Cheese
 * Big the Cat
 * Vector the Crocodile
 * Espio the Chameleon
 * Charmy Bee
 * Mighty the Armadillo
 * Shadow the Hedgehog (rival)
 * Rouge the Bat (friendly rival)
 * E-123 Omega
 * Lumina Flowlight
 * Blaze the Cat
 * Silver the Hedgehog (rival)
 * Emerl
 * G.U.N.
 * Shade the Echidna
 * Classic Sonic
 * Classic Tails
 * Avatar

Rivals

 * Rouge the Bat (friendly rival)
 * Sonic the Hedgehog (friendly rival)
 * Emerl (friendly rival)
 * Storm the Albatross (arch-rival)

Enemies

 * Eggman Empire
 * Dr. Eggman
 * Orbot
 * Cubot
 * Metal Sonic
 * Dr. Eggman Nega
 * Fang the Sniper
 * Chaos (formerly)
 * Void (formerly)
 * Biolizard
 * Black Arms
 * Black Doom
 * Iblis
 * Solaris
 * Ifrit
 * The Babylon Rogues
 * Jet the Hawk
 * Wave the Swallow
 * Nocturnus Clan
 * Pir'Oth Ix
 * Classic Eggman
 * The Time Eater
 * Infinite