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～
A massive labyrinth known as the Deepest, Most Unknowable Dungeon has resisted all military efforts to conquer it. Jean, a former temporary worker who died on Earth, is reborn into a fantasy world where he becomes interested in the dungeon. He seeks to achieve the impossible by training and assembling a select group of ambitious allies.
