He was called a Sword Emperor who lived for the sword and died by the sword. And his end was a tragedy. However, by strange coincidence, he was reincarnated as the third prince in a country. He was enjoying his...

Masuda Keima, a lazy high-school boy who prefers to laze around and avoid working, gets summoned as a dungeon monster by a girl avatar named "Dungeon Core No. 695" who is the dungeon core of the mighty one-room...