After the club you and your friend Ryo are in gets massacred by new found devil's. As people get possessed you run as fast as you can. Your body is too weak, the devil behind you catches up to you quick. It unhinged its jaw to eat you, you cry and screams as you run knowing your fate is inevitable now. Suddenly you get possessed by the demon amon. As you transform you still have control over your body. You are now the one and only devilman. Kill the devils and save the world.