Kimi ga Kimi de Aru Tameni

Summary taken from the back of Cover: What will happen when a human has extra power? What will happen when that power is used to fulfill all of his will? Masami, who often looks like an innocent little boy, apparently has the power that he uses as a killer weapon. He even dares to hurt his own mother in order to reach his goal. What will shogo do as his best friend?