The Black Wizard of Highschool DXD

After dying from the hands of E.N.D. or Etherious Natsu Dragneel, Zeref Dragneel was resurrected by the god Ankhseram. Because of his nature of loving life, he was sent into the world of Highschool DXD as the protector of humanity from the war between the Fallen Angels, Grigori, Devils and Angels. And the Black Wizard sure loves his job.