Fukafuka Dungeon Kouryakuki: Ore no Isekai Tensei Boukentan  

Into the Deepest, Most Unknowable Dungeon, ふかふかダンジョン攻略記～俺の異世界転生冒険譚～

The Deepest, Most Unknowable Dungeon is a city-sized labyrinth that no army has been able to conquer. Despite dying on Earth as a young temp worker, Jean is now reborn in this new world with a fascination for this infamous dungeon. With proper training and trustworthy companions, Jean may have the opportunity to achieve the unthinkable and become a legendary hero in this new fantasy realm.

Fukafuka Dungeon Kouryakuki: Ore no Isekai Tensei Boukentan has been published in English as Into the Deepest, Most Unknowable Dungeon by Seven Seas Entertainment since January 4, 2022.