SatAM had many characters in it that made grand appearences and helped the Freedom Fighters to defeat Robotnik whenever they could. These are the profiles of those characters, the heroes of Mobotropolis.
Sonic, as you all know, is the speedy, blue, fast thinking, wise cracking, hedgehog we all love (or unless you're Robotnik you would think the opposite). Sonic is part of a band of rebels called the Freedom Fighters, they fight against Robotnik to regain freedom. Sonic is a wise cracker and is very proud of it (plus it gave us all the humor back then). Sonic is very kindhearted and helps out the other Freedom Fighters, kicking back or kicking some Robutts(yes, that mispelling is intended). He hangs around with Tails most of the time and the rest is spent with Sally Acorn, someone he really really likes. One thing we know for sure, though, is that Sonic is a LOT braver than Antoine, haha.
Tails is one of Sonic's best buddies in the village of Knothole, home of the Freedom Fighters. He may be young and little (and afraid of some things) but he can pack a punch to help his friends. He likes to just be known as Tails but Sally tends to call him by his real first name, which annoys him. Tails is very smart for his age and does not like to be shoved around. Originally, Tails was not a Freedom Fighter to begin with, he was mainly a little kid that would play with Sonic and Sally. But after he was able to figure out things the other's missed (e.g. noticing the fake Sally) Sally gave him a spot on the team.
Sally Alicia Acorn (or Sally, as she likes to be called) is the princess of Mobotropolis. But when Robotnik sealed away her parents and took control, she started the band of Freedom Fighters to try to keep Robotnik from taking over ALL of Mobius AND at the same time trying to get him out of control of the city. She is, by way of looking at it, a crossbreed of a squirrel and a chipmunk but she's swimming on the chipmunk end of the gene pool. Although she has the "Princess" title in her name, you wouldn't even be able to tell that she's a princess based on how she acts. She's strict and smart but is just as kindhearted as Sonic. She tends to be annoyed by Sonic's "Act first, think later" attitude, but she loves him all the same (and you can tell it too).
Rotor is the big brain of the FF's. He makes all the inventions that they use to take out Robotnik. While he may not be a main fighter of the group, he can defend himself and fight back pretty well when he has to. Mostly, he spends a lot of his time in his workshop creating new gadgets for the Freedom Fighters to use.
Bunnie is a master of martial arts and has the power of her roboticized limbs to enhance her strength (cheater...). She's only half robotic and would've been lost to Robotnik's roboticized forces had Sonic not saved her from the Roboticizer. Bunnie is a very dangerous member of the Freedom Fighters and is the main fighter.