Goblin Slayer Side Story II: Dai Katana, Vol. 5 (manga) — Kumo Kagyu

The party has put down the scruffy men, ending once and for all the corrupted adventurers who had become the scourge of low-level Dungeon-delvers. These six heroes have no intention of resting on their laurels, though. Their quest is not one of money, fame, or mere good deeds -- they intend to defeat the Dungeon of the Dead itself ! To do so, they must venture ever deeper, to the third floor, where a mysterious new threat awaits…!!