Overlord, Vol. 4 (light novel): The Lizardman Heroes (Volume 4)

An army of death approaches a peaceful lizardman village--an army of undead deployed by Nazarick. Its commander is the Sovereign of the Frozen River Cocytus. The lizardman coalition shall face the Great Tomb of Nazarick. The weak are meat the strong shall eat in the merciless world that awaits in Volume 4.