Somehow, before I knew it, I had become the "Demon Lord," the defensive mechanism of a dungeon.

It seemed to be a rather dangerous world, with powerful monsters roaming around and a fierce struggle for survival. I was supposed to develop the dungeon to protect myself and avoid dying, but for some reason, it's turned out to be much more laid-back than I expected. ...How did things end up this way?

Living in such a world, the protagonist, Yuki, exhibits his unflappable nature. Together with the self-indulgent Supreme Dragon girl and the young vampire girl who have taken up residence in the dungeon, he lives each day as he pleases—sometimes laughing, sometimes getting angry, sometimes seeking romance, and sometimes smirking to himself.

Author's Twitter: @Ryuyu_ . The story generally proceeds in a heartwarming, laid-back manner.

Now available in print! Volumes 1-15 are on sale from Kadokawa BOOKS. We did it!

A manga adaptation has been released! Manga volumes 1-8 are now on sale!