Sonic is the fastest thing alive and the eponymous protagonist of the series who possesses incredible super speed and numerous other abilities that are known to be based on breakdancing. He uses these skills to save the world from Dr. Eggman. He is impatient, laid-back, confident, cool-headed and always on the lookout for an adventure as well as to help anyone in need of rescuing.
Tails
Sonic's best friend. He is a young two-tailed fox who can fly for a limited time by spinning his tails rapidly, and has most of Sonic's abilities, including his supersonic speed. He is a skilled mechanic and often takes care of Sonic's biplane, the Tornado.
Dr. Eggman
Real name Dr. Ivo Robotnik, Eggman is Sonic's arch nemesis and the series' main villain. He is extremely intelligent, pompous, bad-tempered, egg-shaped, and has a giant red-brown mustache. Eggman is an expert in robotics with an IQ of 300 whose goal is to conquer the world and build the Eggman Empire. However, Sonic and his friends always stand in his way. In many cases, he is ironically outdone by his own plans.
Knuckles
The last living echidna and Sonic's hotheaded friend and rival. Knuckles resides onAngel Island, where he guards the Master Emerald, the source of the island's ability to float in the sky. Knuckles is very strong; his spiked fists are capable of smashing through boulders as well as allowing him to climb walls. The nature of his echidna dreadlocks allows him to glide in the air for periods of time.
Amy
A young pink hedgehog who has become Sonic's self-appointed girlfriend, first seen in Sonic the Hedgehog CD. Ever since Sonic and Amy met, she has been in love with Sonic and she now wants him to marry her. Amy is quite strong and smashes enemy forces down with her trusty Piko Piko Hammer.
Shadow
Shadow is a mysterious black hedgehog resembling Sonic in appearance and skills, making him Sonic's biggest arch-rival. He is the Ultimate Life Form created by Gerald Robotnik with Black Doom's DNA on the Space Colony ARK over five decades ago. He recently suffered from amnesia but has regained all of his memories since then. He can use Chaos Control to distort time and space.
Cream & Cheese
A naive young rabbit who lives with her mother, Vanilla. Cream's best friend is a Chao called Cheese (which she uses as missile). Because Cream has been brought up like a princess, she does not like being involved in other peoples' affairs. She can fly using her large ears.
Rouge
Rouge is a sassy female bat treasure hunter who's goal is to make all the gems in the world hers and also works as a spy for GUN. She is full of feminine charm and can be very manipulative. She is Knuckles' rival.
Big
A big purple tabby cat who loves fishing. His best friend is a frog named Froggy, whom he constantly keeps losing. Big lives with his buddy in a peaceful hut in theMystic Ruins.
Chao
Chao are a brittle, fleeting and very lovable life form with no defined evolutionary direction. They primarily inhabit clear watersides. By interacting with other living things, they can incorporate their natures and change themselves to adapt to the environment and survive. They are known for their very loving behavior.
Chaotix
A team of misfits who have started their own detective agency. The Chaotix consists of Vector the Crocodile, Espio the Chameleon and Charmy Bee, with Vector being their leader. They met for the first time when they fought against Dr. Robotnik inKnuckles' Chaotix, along with Mighty the Armadillo and Knuckles The Echidna, both of which haven't appeared with them since.
E-123 Omega
The last of the E-100 series of robots created by Eggman and seeks revenge on his master for shutting him down, not being able to realize his potential. Rouge accidentally activated him when trying to free Shadow from Eggman's base. Since then, he has became good friends with both of them.
Babylon Rogues
A group of professional Extreme Gear riders that searches for treasure for their benefits. The leader is Jet the Hawk who is the most talented of Extreme Gear riding, being known as the Legendary Wind Master and shares a rivalry with Sonic in speed.Wave the Swallow, a brilliant and intelligent mechanic, and Storm the Albatross, physically strong in arms but somewhat clumsy, follow Jet's leadership.
Blaze
A female, pyrokinetic lavender cat from a parallel universe. As guardian of the Sol Emeralds, it is her duty to prevent anyone from taking them away from her. She is somewhat shy and tends to conceal her real feelings.
Silver
Silver is a mysterious, white-colored hedgehog from the future. He traveled through time to stop Sonic, who he believed to be the Iblis Trigger causing his time to be ruined. Unlike Sonic, Silver utilizes psychokinesis that allows him to lift objects with his mind and throw them at foes.
Chaos
Chao is an ancient, mutated Chao with high intelligent and god-like powers. With a peaceful temperament, it used the power it gained from the seven Chaos Emeralds to keep the waters around its altar clean and protect its family from enemies. However, when the Knuckles Clan sacrificed its fellow Chao to steal the Chaos Emeralds, Chaos was consumed by anger and used the seven Emeralds to become Perfect Chaos. It then caused a flood and tried to destroy the world until it was sealed in the Master Emerald. Thanks to Sonic though, it has now found peace.
E-102 Gamma
Eggman's shooting robot and the second model in the E-100 Series. Much like Eggman's Badniks, Gamma relied on an animal as a source of bioenergy. After encountering Amy, it began to doubt its allegiance. Eventually, it broke free from Eggman's control to "save" its other brethren from the E-100 Series by setting their animal power sources free. It was destroyed after saving E-101 Mark II.
Tikal
The daughter of the chief of the ancient Knuckles Clan, Pachacamac. Tikal is kind and gentle with a peaceful temperament. She can also communicate with Chaos who was originally feared as a foreign object. She was critical of her father's warmongering and constantly opposed his violent raids of other countries. After Chaos went out of control when Pachacamac invaded its altar, Tikal sealed herself and Chaos in theMaster Emerald. When Chaos resurrected in the modern day, Tikal's soul emerged as a orb to stop Chaos by guiding Sonic and his allies.
Emerl
A mysterious robot from the Nocturnus Clan with the ability to learn skills from others and copy them for himself. He was identified as the legendary "Gizoid", the ultimate combat weapon from 4,000 years ago, by Professor Gerald Robotnik, after the professor discovered him and awoke him during an experiment with the Chaos Emerald. In the end, Sonic destroyed Emerl when he went on a rampage. His name "Emerl" is derived from his affinity with the Chaos Emeralds.
Metal
The robotic counterpart of Sonic the Hedgehog, created by Dr. Robotnik who possesses many of Sonic's abilities including his super speed. He seems to believe that he is in fact the real Sonic and that Sonic is his copy. In Sonic Heroes he betrayed his creator, and took the task of trying to achieve world domination into his own claws.
Marine
A spirited and talkative raccoon girl (who is surprisingly also a neat freak). Active and behavioral, she has a strong longing for adventure. When she encounters something new, she gets so caught up in it that she ignores the surroundings. Her reckless attitude is a frustration to many, but after her adventures with Sonic, she has sworn to grow up.
Chip
An ancient deity from the beginning of time and the incarnation of light, day and rebirth. He got his name from Sonic after the hedgehog noticed Chip's affection for the Sundae Supreme ice cream. He is a tremendous glutton and always hides chocolate somewhere on him. He is bright and friendly, but also a bit goofy. While easily frightened, he possesses enormous powers.
Sticks
A crazy and paranoid badger girl from the Sonic Boom franchise who has appeared in a couple of Sonic the Hedgehog mainstream medias. She lives at the edge of the forest. Because she has lived in the wild since early age, Sticks is feral and without common sense. However, she is a skilled hunter and an expert at using boomerangs. She is also a good friend of Amy.
Eggman Nega
The opposite but equally evil Dr. Eggman known as Eggman Nega. Like Silver the Hedgehog, Nega is from the distant future, and is Eggman's descendant. Similar to his ancestor, he tries to steal the mystic gems of his world to rule the universe. He is cunning, cold-hearted and a genius, just like the true mad scientist. However, he can easily be seen as a different doctor by his deep shades, nasal voice and gray mustache.
Orbot & Cubot
Dr. Eggman's robots, who he made for the purpose of aiding him. The round one is Orbot and the square one is Cubot—together they are a duo.
Orbot is the brains and more serious and firmer one. Although he carries out his master's orders with devotion and he completes his work diligently, his spiteful sarcasm sometimes angers Dr. Eggman. He is the straight man to Cubot’s funny man.
Cubot is a good-hearted and easy-going robot. Even though he is supposed to be built with the same CPU as Orbot's, he is somehow slow on the uptake. He admires Dr. Eggman, but his behavior is like a sloth that cannot be bothered to be woken up, so he does nothing but upset him. Cubot is the funny man to Orbot’s straight man.