Goblin Slayer: A Day in the Life, Vol. 3 (manga)

Goblin Slayer, Spearman, and Heavy Warrior have taken a quest to explore a ruined city. This ad hoc boys' party turns out to work together well, and soon reaches the city center, where a mighty foe awaits… Meanwhile, another party uncovers an artifact which could shape the fate of the world, and must defend it against an army of undead!!