Sonic the Hedgehog - Hero of the planet Mobius.
Miles "Tails" Prower - Sonic's twin-tailed best friend.
Knuckles the Echidna - Guardian of the Floating Island and the Chaos Emeralds.
Dr. Ivo Robotnik - A mad scientist and former Dictator of Mobius.
Amy Rose - Female hedgehog who is an expert at archery, and has an excellent aim with most hand-held guns. Who needs a hammer?
Grimer - Robotnik's chief scientist.
Super Sonic - When Sonic absorbs too much Chaos Energy, he transforms into this all-powerful incarnacion of the evil side of his personality. They were later separated, and became two distinct entities...
Johnny Lightfoot - A rabbit who was one of the members of Sonic's Freedom Fighter group, before he became the first - and only - character to die in STC.
Porker Lewis - A shy pig, but a technological genius. He suffered a nervous breakdown after being held captive by the Brotherhood of Metallix.
Chaos - An extremely powerful water monster. In STC, he was created when a Drakon Prosecutor absorbed phenomenal amounts of Chaos Energy.
Tikal - Daughter of Pochacamac, the Chief of Mobius' ancient race of Echidnas.
The Drakon Empire - The Drakon are an ancient alien race of fish who created robotic bodies for themselves and settled on Mobius in the ancient past. Thousands of years ago, they fought a war against the Echidnas of Mobius.
Metallix - Robot Sonic built by Robotnik and Grimer to kill the hedgehog. Known in other continuities as Metal Sonic, Silver Sonic and Mecha Sonic.
Pochacamac - Chief of Mobius' ancient race of Echidnas. Yes, that's how the name's spelled in STC!
Brutus - An SBS Trooper programmed with Robotnik's brain waves to be his second-in-command. He later turned on his master and attempted to kill both him and Sonic.
Doctor Zachary - Apart from Knuckles, the last of the ancient race of Echidnas. Unlike Knux, he's a baddie!
Shortfuse the Cybernik - An innocent squirrel named Shorty was once captured by Robotnik and imprisoned inside an advanced suit of armour to be the ultimate killing machine. However, he resisted the Doc's brainwashing and now fights evil alone! Imagine Marvel's Iron Man, but in silver armour. And replace 'Man' with 'Squirrel'. And 'Iron' with 'Megatal.'
Tekno the Canary - Like Porker Lewis, a technological genius, but much braver. She has teamed up with both Shortfuse and Amy many times.
Ebony - A cat possessing strong magical powers. When SuperSonic lost his powers and memory, she was the only one who trusted him.
Pyjamas - Ebony's psychic companion.
Norris Wimple - Mobius' resident nerd.
Fabian Vane - The worst singer on Moius. Has all the musical talent of a deaf chimpanzee.
Captain Plunder - Captain of a vicious group of Sky Pirates (he appeared long before Skies of Arcadia came out, by the way)!
Simpson the Cat - The cartoon-like companion of Captain Plunder.
The Tantaror - A supremely powerful race of alien beings.