Suikotsu

Suikotsu has two, definite split personalities. One, a gentle, philanthropist doctor who looks after orphans; the other is a sadistic, Wolverine-wannabe killer that earns him spot in the Seven-Man Army. When his evil side takes hold he seems topossess a dry sense of humour and a insatiable desire for blood, while when his good side is in control he often hallucinates that he has blood on his hands. He may have a third personality, as shown after he falls off a rope-bridge; this personality seems to be a combination of his other two. -Inuyasha.wikia.com