Reborn in another world as a demon lord, Yuki plans to use the incredibly handy online store that is the DP Catalog to create a super sinister dungeon where he can live the easy life! But the moment he starts his new life, he encounters the unimaginably strong Supreme Dragon. Just when he thinks the end is already nigh, things take a bizarre turn in his favor! The Supreme Dragon transforms into a lovely young girl hell-bent on freeloading off him. And she’s not his dungeon’s only new resident. While taking care of his new family, Yuki experiments even more with the Catalog by learning how to create his own weapons. Their idyllic days don’t last long, though, as an unexpected menace appears...