The Soulmonger was an immensely powerful artifact constructed by the demilich Acererak and a coven of hags he enlisted to aid him. The artifact was not only able to drain the life of individuals who had been resurrected at some point in the past, but also to collect the souls of dead creatures from all over Faerûn.
The Soulmonger was originally constructed by the lich Acererak and a coven of hag witches. The intent was that it would harness souls from all over Toril and feed them to an atropal he had brought from the Negative Energy plane, planning for the atropal to become a god of death that could ravage the Prime Material plane. For the atropal and the Soulmonger's protection, it was placed on the lowest level of the Tomb of the Nine Gods, a dungeon constructed to kill adventurers for Acererak's phylactery. The Soulmonger was watched over by the three hags that had aided Acererak, and Acererak kept an eye on it himself.