Highschool of Apocalypse: Tale of the Strongest Satan

After destroying his world, Canopus,a human who consumed the 666 from another universe and the world's strongest mage and warrior, was bored.He had nothing to do other than watching over his ruined world that is:Until a failed summon takes him to the current DxD universe and fate allows him to become a Devil.(Rewrite of Rise of a Maou)(OcxHarem)