This little ****er had us all convinced that he was Oro's pet, especially when he was pulling all that "fake smile" crap.
He convinced the whole Narutoverse that he was Madara Uchiha. Props. Not to mention he played the part of Tobi, who we all thought needed a brain scan (to say the least)
I'll be damned if I didn't think he was evil. Truly, he was an actor who was committed to his role until the very end.
Any other nominees?