He's the main dude - and it's easy to see why. He's a blue hedgehog whose got speed, attitude, those white gloves, and a huge cast of friends and foes. Sonic has an ego that stems from his ability to move faster than anything else that breathes, and he can seem full of himself at times. Still, he has a free, adventurous life and never stays at the same locale for too long, fighting Robotnik all across Mobius.
He's an evil genius who meticulously plans out ways to conquer Mobius - perfectly devised, fail-proof plans - but gets thwarted again and again by Sonic. Usually his plans involve stealing the Chaos Emeralds for his own devious uses. He may "HATE... THAT... HEDGEHOG!", but he may also secretly admire him as well.
A two-tailed, smart little fox who joined Sonic's company as his right-hand man. Sonic and Tails are best friends, and their abilities are complementary to one another. Tails has the smarts and can build devices to help thwart Eggman, as well as fly by whirling his two tails fast enough. Sonic has the muscle and can take the driver's seat. Tails is very young, but Sonic as well as anyone else can see his potential, a potential Tails is all too adamant to prove.
Amy Rose has been infatuated with Sonic from day one. He's not much of a romantic settle-down kind of guy, but that doesn't stop Amy from trying. Sonic saved Amy from Metal Sonic after they first met, but since then she's proven to come in handy in her own right. She's super strong, and can use her Piko Piko Hammer to break just about anything - maybe even Sonic if he doesn't come to his senses!
Metal Sonic is a robotic version of Sonic built by Dr. Eggman to destroy our blue blur. He's just as fast and can perform most of the abilities Sonic can. He's also cold and unfeeling, without any identity of his own as he takes everything he is from Sonic.
Knuckles' destiny is to guard the Master Emerald that keeps Angel Island, his home, afloat. He is gullible though and has been tricked by Eggman into fighting Sonic on various occasions. Thus, he is known as Sonic's "Friendly Nemesis". Knuckles is super strong, and can use his knuckles to dig as well as to climb. He has a temper, and finds trouble taking things jokingly at times. Even when he's fighting Sonic, though, he always intends to do what's right.
Created by Professor Gerald Robotnik 50 years ago in his scientific quest to discover a path to immortality, which he'd hoped would cure his daughter, Maria, of Neuro-Immune Deficiency Syndrome. Maria ended up dying in front of Shadow, though not before making him promise to save the world from something only Shadow knows. The experience shook him, and having been brought back to consciousness by Robotnik, he has a bitter, dark personality. He's much more powerful than Sonic, can use Chaos Control with the power of the Chaos Emeralds, and has speed to rival Sonic too. He sides with either Sonic or Eggman depending on his own personal needs.
Raised by her doting mother, Vanilla, Cream is a sweet, innocent young rabbit who uses her Chao pal, Cheese, to attack enemies from a distance. She can also fly by flapping her ears, though not as effectively as Tails can.
Arranged in order of appearance, this list collects the characters of the Sonic the Hedgehog series. Only the main ones, though - we don't need too many Listal profile pages for guys like Ray the Flying Squirrel and Rotor Walrus!