Shadow's outer appearance is quite unique compared to the other characters. He prefers to work alone and distances himself from essentially everyone, with few exceptions. Though soft-spoken and reserved, he never bluffs; if he makes a threat, he has every intention of carrying it out. This is seen in Shadow the Hedgehog, when Shadow warns Sonic in one of the storylines that if he were to try to stop him, the hedgehog would inevitably destroy his blue counterpart. Shadow views Sonic as his rival and equal in all aspects of his life, but still sees him as annoying and foolish as he can be. Like Knuckles used to be with Sonic, Shadow has a rivalry with Sonic due to their animosity with each other in terms of how they view their own methods of justice and morality, but will work together despite certain problems they have with one another, and readily come to the others' aid. Shadow is known to treat others in a very callous manner, and in combat, he displays a natural "killer instinct" that Sonic lacks.
Debut is "Sonic's Adventures of Kingdom Hearts "
Shadow the hedgehog makes his debut, after the battle with Leon as Sora and Sonic recover. After, defeating Eggman's Machine. Shadow and Tails Join Sonic the reclaim the reat of the emeralds form the evil Doctor. In the end Shadow go to the other side of the Door of Darkness to help seal the door for good.
Confusion in "Sonics Adventures of Kingdom hearts 2"
In the mid-summer of 2010, Sonic's Adventures of kingdom Hearts 2 was released. The confusion began as people thoguht Shadow was Mephiles in his hedgehog form. This was believed to be true. Until, when Sonic and Sora come back to Twilight Town and see that Shadow was himself and not the dark hedgehog from earlier. In a deleted scene, Shadow confronts Sonic and tells him what happened after the door was sealed. In this, Shadow tells Sonic that the effects of Chaos Control took out the darkness of his heart and created a new Mephiles that was good and unlike the oruginal.
Shadow and Molly
When Shadow first saw Molly Harper, she remind him of his old friend, Maria. Shadow almost has tears in his eyes when Molly got killed in Flight 180, but now he is releif that she is revived as a hedgehog. He will always protect her from any danger.
- Shadow has the power of Uchiha clan's jutsu, The Sharingan. It's reveal in Tsunade's Test during the battle between Sonic and Shadow vs. Naruto and Sakura.
- Shadow is the ultimate life form, created by different people like Black Doom, Ansem the Wise, Gerald Robotnik, William Bludworth and Madra Uchiha