Marrowthirst rules the Fallow Kingdom of Voldyr, his realm having extended considerably from his original charge of the Corpse Orchards, although in his madness he thinks he is the warden of this prison where corpses are lashed to the trees. His stronghold is Voldyr Keep, from where he hurls any troublesome prisoners into the unending dark beneath the fortress.
In the Age of Sigmar, Lord-Celestant Yurvash of the stormcast Anvils of the Heldenhammer marched into his lands, having fought through the defenders of spire-tombs of the deathrattler queens in the Gloomdream Vales. He had been tasked with securing the Gate of Corpses a Realmgate to the Realm of Azyr. Informed of these invaders, marrowthirst raised his mordant armies and fell upon the 300 stormcast as they entered the Corpse Orchards - all of the Anvils were slain and sent back to Sigmar's realm..