Major character(s), not necessarily the main character, assume the role of a dungeon master. Dungeon master is a character that owned a dungeon, and is different from a dungeon guardian whose role is more readily attuned to dungeon's administration tasks.
One day, I woke up only find out that I’d become a Demon Lord, an individual responsible for protecting a dungeon. The world I’d been spirited away to was one filled with violence. Gigantic monsters wandered through it and competed with each other each and every day for the right to survive. I had no choice but to strengthen my dungeon’s defenses in hopes of living another day—or at least that was what I’d thought. For some odd reason, I instead ended up spending my days in relaxation and bliss. This is Yuki’s story, my story. It tells the tale of how I spent my days after settling down in a dungeon with a self indulgent, “supreme” dragon girl and a young vampire.
“Hey, hurry up and massacre those bandits!” “No way, I don’t want to work…” Spending my daily life in leisure, that was my pastime—until I was summoned into another world and met a blonde loli introducing herself as Dungeon Core No. 695. “Save my dungeon. By the way, if the dungeon core is destroyed, you’ll also go down with me as the dungeon master.” A dungeon with a single room. Moreover, one already controlled by bandits. This is a [Checkmate] no matter how you look at it. Guess there’s nothing to do but somehow get out of this situation so that I can [Not Work]!!