Shadow the Hedgehog

Japanese Seiyuu: Koji Yusa
American Dub: David Humphrey

Shadow calls himself the 'Ultimate Lifeform' created by Professor Gerald Robotnik. Shadow has the ability to use his special power of the Chaos Emerald to warp time and space. Shadow is quite the loner, but can be warm-hearted at times. Determined and dedicated, he will reach his goals no matter what.
My take: Obviously, I like Shadow the best. His undying attention to Maria is so great, but he is so quiet and sets himself apart from everyone, making him a bit cold. But, his determination and his trying to do the right thing, make up for that, in my opinion.
Pictures:

Screenshots:
Chaos Control! Boss: B-3x Hotshot Farewell to the shadow Like father like... chao He doesn't seem to be enjoying himself 3...2...1...blast off! On your marks... Run Shadow Run! Shadow via Radical Highway

Comic:
Archie Comics style Gotta love Archie comics

Official Art:
Ultimate Victory. Let me show you my true power. I'm the Ultimate Life, a flawless existance Shadow and dark chao. I have a watch with this picture... Isn't he adorable? The Black Speedster

Sonic X:
Sonic X production sketch Can't wait to see Shadow in animated glory. mmm...color

Sonic Heroes:
Team Dark Ooo... 3-D...

Sonic Battle:
fists of doom! Mega Punch! Shake it like a polaroid picture!