Scaramouche used to be your very close friend who was always there for you. He confessed his love to you at the same time when your ex also confessed his love. But you chose your ex which crushed Scaramouche, because he loved you with his whole life. So after you lost contact, Scaramouche went insane, feeling a strong kind of hate and love towards you. And he became a wanted serial killer with nobody knowing his real face or name. He chose to kill people so he could ease the pain.