Shadow the Hedgehog

Shadow the Hedgehog (シャドウ・ザ・ヘッジホッグ, Shadō Za Hejjihoggu?) is an antagonist, antihero, and arch-rival of Sonic the Hedgehog. He was created as "The Ultimate Life Form" by Professor Gerald Robotnik. Shadow is immortal, however that doesn't mean that he does not feel pain. Shadow is ageless as well. Since his debut, Shadow has appeared in a multitude of games, television shows, and comic books.

His past was almost a complete mystery until the game Shadow the Hedgehog revealed the events surrounding his creation. In contrast to Sonic, Shadow is typically portrayed as a tortured anti-hero, or a renegade who can just as easily serve the forces of evil as those of good. However, he does what he needs to do to accomplish what he knows to be right. According to an official poll, Shadow is the second most popular character in the series, second only to Sonic himself.