Demon King of the Royal Class

Upon dying, the author of "The Demon King is Dead" is given two choices: go to hell or be reborn in his novel and survive till the end. The problem? He's reborn as Baalier Junior, a weak demon prince, after his realm was conquered! To make things worse, his attempt to escape somehow gets him enrolled as a student of the Royal Class in Gradias Temple, a prestigious human school. In the midst of plotlines and political schemes, can this author keep his identity a secret and reach a happy ending?