Rise of the True Demon King: Iruma!

Despite being a human, Iruma has grown to love the Underworld as his new home. And yet, a familiar group of demons has come to threaten his new home, and just when things were starting to feel normal! Luckily, and old friend appears with an answer, one that Iruma dreads. There's only one way to save the Underworld, and that's by becoming the new Demon King! Rated M, just in case!