Since they made Death Note into a DS game in Japan, I guess I could suggest L. Definitely the epitome of Asperger's characteristics. They even made a page about it too.
I might suggest Alucard from Castlevania, considering he doesn't talk much either, and doesn't display his emotions very well. Apparently, the other characters imply that he might not have liked killing his father, Dracula, but that emotion never displayed itself when Dracula did die. He was also devoted to destroying Castlevania, even if it meant killing Richter. The only thing that doesn't scream Aspie about him is he's actually elegant, not clumsy.