One day, school teachers come as freeloaders to the inn run by his parents. Hiro Kazami, a high school boy, decides to take care of the inn and his future. Under one roof the forbidden harem romantic comedy begins.

Before I realized, I had become the guardian of a dungeon, a Demon Lord. I was suddenly in a dangerous world with giant monsters loitering around, fighting for their existence, so I thought to go about developing the dungeon in order to not die but —- fo