Knuckles the Echidna (Classic Sonic's world)

Knuckles the Echidna (ナックルズ・ザ・エキドゥナ) is a character that appears in the Sonic the Hedgehog series. He is an anthropomorphic echidna and Knuckles the Echidna's counterpart from another dimension set in the recent past. He is also the guardian of the Master Emerald, a powerful ancient relic which is his solemn duty to protect from anyone seeking to abuse it.

Appearance
Knuckles is an anthropomorphic echidna with red fur that covers most of his body, peach skin that covers his muzzle, and white fur that covers a small part of his neck, and black eyes. He also has seven spines and a short tail along with spiked knuckles.

He wears red and yellow shoes with green cuffs and a grey plate on top. He also wears white gloves with a sock-like cuffs on his hands.

Past
Knuckles' early history was most likely largely the same as his mainstream counterpart's up until at least some time after the West Side Island incident.

Sonic the Hedgehog 3 & Knuckles
In Sonic the Hedgehog 3 & Knuckles, Angel Island received an unwanted visit by Dr. Eggman when the Death Egg crash-landed on the island. To buy himself time to rebuild the Death Egg, Eggman tricked Knuckles into believing that Sonic the Hedgehog and Miles "Tails" Prower were going to steal the Master Emerald. Enraged, Knuckles clashed with the duo all over the island after their arrival. Some time after making the Death Egg crash once again, Sonic and Tails managed to convince Knuckles about Eggman's true nature, especially after the evil scientist stole the Master Emerald for himself. Sonic and Tails subsequently managed to destroy the Death Egg and return the Master Emerald to Knuckles. Not long after, Knuckles had to contend against an Egg-Robo and a robotic doppelgänger of Sonic for the possession of the Master Emerald. Luckily, with last minute help from Sonic, Knuckles was able to return the Master Emerald to its rightful place.

Sonic Mania
In Sonic Mania, sometime after Sonic and Tails saved Angel Island, Knuckles was relaxing on his island when he heard a loud noise. As it turned out, five Egg-Robos called the Hard Boiled Heavies had excavated the island in search of a mysterious gemstone called the Phantom Ruby. Knuckles prepared to fight them but the robots knocked him out, activating the ruby and transporting the echidna away. Knuckles ended up in Green Hill Zone, along with Sonic, Tails and the Egg-Robos. Having been upgraded by the Phantom Ruby, the Hard Boiled Heavies retreated with the ruby, leaving Knuckles and co. to chase them down.

The trio eventually faced Dr. Eggman and defeated him. Soon after his defeat, Eggman found trouble in controlling the Hard Boiled Heavies again. As such, the evil doctor took the Phantom Ruby for himself by force, causing Knuckles, Sonic and Tails to get sent away by the gem's power. Not set back by their displacement, Knuckles and co. continued their pursuit of Eggman, occasionally clashing with the Hard Boiled Heavies along the way. During the adventure, Knuckles found the leader of the Hard Boiled Heavies, the Heavy King, trying to steal the Master Emerald when the echidna got separated from his friends. Not prepared to let history repeat itself, Knuckles fought off the robot and caught up with his friends.

Eventually, Knuckles, Sonic and Tails found out that Dr. Eggman had used the power of the Phantom Ruby to make Little Planet reappear in its mechanized state. There, Eggman and the Hard Boiled Heavies housed a new base of operations: the Titanic Monarch. The trio made their way to the heart of the robot where they faced Eggman in his Phantom Egg mech and four of the newly upgraded Phantom Heavies. Despite the odds, Knuckles and co. managed to defeat Eggman, resulting in the breakdown of the Titanic Monarch. While Knuckles and Tails managed to escape, Sonic and Eggman were transported to another dimension. Soon after, Little Planet was freed from its chain once again and Knuckles and Tails smiled upon seeing a star constellation of Sonic in the sky as the planet vanished.

Sonic Mania Adventures
Around the time of Sonic's return, Knuckles took the Master Emerald from its shrine and began bringing it elsewhere. His reason for doing so was to keep the Master Emerald safe after all the trouble that had showed up since Sonic and Eggman's arrived on Angel Island.

Just as he had found a safe place for the gem, Knuckles heard someone nearby, and thought it was Eggman, the Heavy King, or even Sonic coming to take the Master Emerald. However, the stranger turned out to just be Ray the Flying Squirrel, who was looking for Mighty the Armadillo. Just as Knuckles informed Ray that he had not seen Mighty however, he threw Ray away for trying to touch the Master Emerald. Three RhinoBots soon after showed up, which Knuckles destroyed. However, he then saw that the Master Emerald had been stolen while he was occupied. Spotting then the Tornado dragging the Master Emerald through the sky, Knuckles assumed Sonic had stolen the Master Emerald, and began chasing the biplane. Knuckles soon after spotted Sonic and Tails heading towards a foreign Eggman base on his island and began chasing after them.

Upon reaching Dr. Eggman's base, Knuckles immediately prevented Metal Sonic from harnessing the power of the Master Emerald. by punching both him and Dr. Eggman into the distance. Having successfully retrieved the Emerald, Knuckles walked off, ignorant of Sonic, Tails, Mighty, and Ray who stared at him.

Personality
Knuckles is a hotheaded loner who is very loyal to his duty as guardian of the Master Emerald. The safety of the Master Emerald is his primary concern, and when he is working to protect the precious gem, he stay uninterested (bordering on ignorant) about the unrelated matters surrounding him. His temper can sometimes get the best of him, making him run into situations head-first without thinking. Knuckles can also be quite gullible, but he is capable of learning from his mistakes. To make up for it, Knuckles is heroic and does not hesitate to help those in need.

As a result of all the trouble that has appeared on his island after Sonic and Eggman arrived, Knuckles has become increasingly more determined to keep the Master Emerald safe, bordering on paranoia; when Ray tried to touch the Master Emerald out of curiosity, Knuckles responded by grabbing Ray and throwing him away. He also still does not fully trust Sonic, whom he is willing to think of as a thief just wanting to steal the Master Emerald.

Powers and abilities
Knuckles' trademark ability is his immense superhuman strength. His strength seems to lie in his upper body, particularly in his arms and fists. He has high endurance and can run at speeds fast enough to keep up with Sonic. Knuckles is also an experienced swimmer, has sharp reflexes and acrobatic skills, and is well-versed in movements involving his hands.

Knuckles is capable of using the Spin Attack, Spin Dash and Spin Jump, which are techniques where he curls into a concussive ball or cutting disk and directs himself at his targets. He can also glide over long distances by trapping air underneath his dreadlocks and climb almost any surface with the aid of the spikes on his gloves.

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.

Friends/allies

 * Sonic the Hedgehog (close ally)
 * Miles "Tails" Prower (good friend)

Enemies

 * Dr. Eggman
 * Hard Boiled Heavies
 * Heavy King
 * Heavy Gunner
 * Heavy Magician
 * Heavy Shinobi
 * Heavy Rider
 * Metal Sonic