According to Syndra Silvane, the Soulmonger is an artifact responsible for the death curse. Its exact whereabouts are unknown, though Syndra’s contacts have narrowed its location to the continent of Chult.
Grandfather Zitembe, head priest of the temple of Savras, Port Nyanzaru, consulted with the spirits on behalf of the party. He saw “a jungle city, far to the south, enclosed by cliffs and crawling with snakes” and a “black obelisk draped in vines,” but he dared not peer any further.
In her own visions, the great Oracle of Orolunga, Saja N’baza, sees that Omu, a forgotten city to the south, is the probable location of the Soulmonger and thus, the origin of the death curse.