Lv1 Maou to One Room Yuusha

Ten years ago, the hero Max defeated the Demon Lord and saved humanity, after which the companions who created that legend went their separate ways. When the Demon Lord finally resurrects in a small body, he immediately visits his old enemy for revenge and receives a shock worse than his earlier defeat: Max has become a messy recluse living alone in a cramped apartment, barely resembling the hero he remembers.

Rather than kill such a disappointing rival, the Demon Lord decides to stay close until Max becomes worthy of a proper rematch. Between domestic arguments and memories of their glory days, an old conflict among Max's former companions begins threatening a new crisis, leaving the fallen hero and his former enemy far more entangled than either expected.