Júša, jamemasu

After defeating the Demon King, former hero Leo Demonheart is learning that he was just a little too good at what he did, to the point that many now suspect that his real goal was to become the Demon King himself. Which, given that his name is Demonheart and he was created as part of a secret project, is perhaps not as far-fetched as it sounds, but now nobody wants to employ him, and a former hero has still got to eat. So, he applies for a job with the Demon King Echidna herself... but she doesn't want him either. Fortunately, some of her subordinates are more appreciative of his skills, and if he wears a disguise, he might just get away with becoming the new bad boy on the block! (Sentai Filmworks)