Borem of the Lake of Boiling Mud was a minor deity slain by Bhaal, Myrkul, and Bane using an artiface called the Jathiman Dagger. With the power thus gained, the Dark Three went on to challenge Jergal for his throne.
Borem's Quagheart, his actual heart, is a major artifact in Faiths and Pantheons,
as is the Jathiman Dagger that killed him. They're buried under a
menhir on Mezeketh Isle near Saerloon, and the inscription links him to
Jhaamdath. Pages 169-170.
Journal Entry 19:
A black bound tome written in a strange halting hand.
...and settled foremost in the half of Minor Courtiers were the lesser
powers: Maram of the Great Spear; Haask, Voice of Hargut; Tyranthraxus
the Flamed One; Borem of the Lake of Boiling Mud; and Camnod the
Unseen. These too fell down and became servants of the great lord
Bane. - Pool of Radiance computer game booklet
- 1056 reads