The Demon Lord shows up at Max's apartment ready for the ultimate rematch, finds a man in sweatpants who hasn't left his room in years, and somehow becomes his only friend. What could've been a one-joke premise instead builds real affection between two characters who have nothing left to lose, their chemistry so genuine that you stop laughing at the setup and start caring about whether Max ever leaves that couch. The show admits its animation budget is thin in places, but it doesn't matter because the actual story, about a washed-up hero and a demon lord finding purpose in each other instead of in glory, is where all the money went.

A demon lord returns from defeat seeking vengeance against the hero who humiliated him a decade ago. His revival is incomplete, however, and he comes back in the body of a child. What he finds is Max, once a gallant defender of humanity, now a shut-in slob with no interest in a rematch. Disappointed but determined, the demon lord moves in with his old enemy, hoping to rebuild him into an opponent worth beating. As he learns what happened during the ten years he was gone, he starts to realize there is a story behind Max's fall that he never knew. Adapted from a manga by Toufu, the series is a comedic, ecchi-tinged fantasy built on the clash between a villain's straightforward revenge and a hero who no longer cares.