He is Diablo!

In an attempt to make her 3 year-long crush fall in love with her, superstitious high school-aged Yamada Meiko accidentally performs black magic and summons the devil Lucifer, who for some reason reappears at her school the next day as her homeroom teacher. Convinced he is an angel (after all, he had white wings!), she asks him to grant her a wish. Little does she know what a high price she will have to pay for her seemingly innocent request...