The Soulmonger is a device housed in the Tomb of the Nine Gods that stores souls for the atropal to eat. It is the source of the death curse, and is guarded by the Sewn Sisters. Lilith was the one who first warned the group about the death curse.Evelyn gave her soul to protect her friends from the death curse. Paultin stopped her soul from being devoured by the Soulmonger.  Even with the protection, the group was slowly wasting away from the death curse. Ultimately, Evelyn destroyed the Soulmonger with her holy light.