I'm Standing on A Million Lives Volume 11

To solve an oppressive situation that has kept hundreds of blacksmiths working around the clock for years, Yotsuya and his companions must help defeat the mysterious beast that's thwarted all would-be challengers. While some of the party heads to the mountains with the latest contingent of soldiers hoping to slay the undefeated monster, Yotsuya remains behind in town to gather information and has an unexpected reunion with an old acquaintance. However, they clearly aren't the person Yotsuya used to know anymore...