Knuckles the Echidna (Classic Sonic's world)

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 Knuckles the Echidna's counterpart from an alternate dimension set in the recent past that has a history that closely follows the mainstream universe's. 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.

Sonic the Hedgehog 3 & Knuckles
In Sonic the Hedgehog 3 & Knuckles, Angel Island received an unwanted visit by Dr. Eggman. Eggman has 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. 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 had stolen 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 would have to contend against an Egg-Robo and a robotic doppelgänger of Sonic for the possession of the Master Emerald again. 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. 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 newly upgraded Egg-Robos, who 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. Due to this, the evil doctor stole the Phantom Ruby for himself, causing Knuckles, Sonic and Tails to get sent away by the gem's power. With this, 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 for himself. Not prepared to let history repeat itself, Knuckles fought off the robot and caught up with his friends.

Soon, 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, 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.

Personality
Knuckles is a hotheaded loner who is very loyal to his duty as guardian of the Master Emerald. 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 hesistate to help those in need.

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 a 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 and climb almost any surface thanks to 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 (friendly rival)
 * Miles "Tails" Prower

Enemies

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