the Demonsking (English Version)

Alexander comes to a new school, and everything changes. When his roommate is murdered, he realizes that something is amiss. He encounters the Demons, a group of former bodyguards to the old king of Akadia who have now become assassins. He also learns that he is the reincarnation of the Demon King, and Alex becomes the leader of this group. Along the way, he falls in love.