Sseth

Sseth (also known as Merrshaulk) was the chief god of the reptilian yuan-ti, a chaotic evil mastermind of traps, poison, and murder. His clerics were known as vrael olo. His symbol is a flying snake with bared fangs.

Worshippers
Sibyl was once the avatar of Sseth.

History
Like all the other gods of Toril, during the Time of Troubles Sseth was cast to the Prime by Lord Ao. He appeared over the jungles of Chult as an enormous magic-using winged snake, exhorting his priests to gather their strength. But as he slept in his lair, he was bound by the Mulhorandi god Set into a magical captivity in the Abyss; the Father of Jackals usurped his portfolio and continues to grant spells in Sseth's name (using his own Air, Darkness, Evil, Hatred, Law, Magic, and Scalykind domains).

The vast majority of yuan-ti were unaware of this; those who knew something were vaguely aware that the Slitherer Supreme was distressed in some way. Set's binding upon the yuan-ti god was imperfect, and fragments of nightmares sometimes appeared in visions to his followers. Those who saw them generally interpreted the dreams to mean that Sseth was upset or angry. Repeated divinations determined that Sseth was in distress of some sort, prompting many yuan-ti to quest for answers.

A small minority of Sseth's followers learned a partial truth, that their god was losing a battle with another, and that the Okothian sarrukh were to blame. Those who knew this kept it quiet, hoping to gather more information on the matter before revealing it. The Okothian sarrukh knew the full truth, but were sowing disinformation among the yuan-ti to delay and confuse any investigation.

If Sseth is freed, he will likely declare war upon the Mulhorandi god, and (possibly) ally himself temporarily with Set's foes.