Basically a black and red version of Sonic the Hedgehog. He is
supposevly the Ultimate Life Form created by Professor Gerald(Eggman's Grandpa). He first appears in Sonic Adventure 2 where he has a bad case of amnesia and can't remember his purpose. He teams up with Eggman and Rouge the Bat to find all the emeralds. He calls Sonic a poser and makes him his rival until the end of the game where they all team up because the Space Colony ARK is gonna crash with earth. To kill huge thing, he becomes Hyper Shadow with the aid of the Chaos Emeralds. After Hyper Shadow and Super Sonic kill the
Finalhazard, Shadow "dies" and falls to earth. Shadow appears again in Sonic Battle which is a version of Super Smash Bros only Sonic Style. Shadow isn't very important in this game though, as Emeral the Robot takes all the glory of beatin Eggman. In Sonic Heroes, Shadow teams up with Rough and Omega to form Team Dark to go after Eggman. In the end they find that Eggman is not the true enemy, but Metal Sonic is. So Team Dark teams up with
Team Sonic(Sonic,Tails, and Knuckles), Team Rose(Amy,Cream and Big)and
Team Chaotix(Espio,Charmy and Vector) to kill Metal
Overloard and save the planet again.