A

He's the other twins of Ran. He loved Ran and he believe that Ran wouldn't be happy if he's not with him. When he know that Ran is happy with others person, A get angry and he try to kill Gingetsu (He killed B before because B and Ran get to close) in order to take Ran back to him. But then after he know that Ran wouldn't go back with him even with Gingetsu death. He leave Ran with Ran's promise that he will not love anyone else more that A. (Source: Happiness)