Death march to the parallel world rhapsody, vol. 4 (light novel), paperback/hiro ainana

When Satou and his party cross into the famously unsafe Muno Barony, they find ramshackle villages, fortresses inhabited by the souls of the dead, and all manner of unrest.

Amid the chaos, Satou meets a girl who happens to be the Barons daughter and stumbles across a conspiracy.