Borem

Borem of the Boiling Mud was some kind of divine being, possibly a primordial who remained on Toril after the split between Abeir and it's twin. He is known to be one of the Seven Lost Gods.

In -359 DR Borem became active after long years of appearing as a simple muddy river. After a hot summer the river broke it's banks and became a lake in the space of a tenday of rainfall. In their quest for godhood, the adventurers Bane, Bhaal and Myrkul attacked Borem in his homeplane after making the connection between him and the river, killing him and stealing his divine essence before heading towards Cormanthor.