This is the Dungeon. The address is Royal Capital Apartment, Room 103.

I—Kishikawa Yuu—suddenly found myself copied from Earth with only my memories intact, transformed into a race called Dungeon Master. "Create a dungeon, lure in foolish adventurers, and offer them up in a blood sacrifice!" That's what Leche, the angel assigned to support me, said. But I had no intention of creating an ordinary dungeon. Because this world was incredibly unstable. Left alone, hell would manifest in the blink of an eye—it was a defective world. Dungeon Masters and angels were nothing but management personnel tasked with preventing that. For that reason, I decided to create a dungeon that would be called unprecedented in this world. As the installation location for the Dungeon Core, the very heart of the dungeon, I chose a single room in an apartment building located in the royal capital of the Alven Kingdom.