Demon King Daimao (2010)
Original Title: いちばんうしろの大魔王
Demon King Daimao follows Akuto Sai as the lead character, who on the day he enters Constant Magic Academy, receives a very unexpected future occupation aptitude test result: “Demon King.”
Demon King Daimao - watch online: streaming, buy or rent
Currently you are able to watch "Demon King Daimao" streaming on Crunchyroll for free with ads.