Zehir

Zehir is an interloper deity who came to Toril shortly before the Spellplague but was a relative unknown power until after that event. He has an affinity for snakes.

Worshipers
Zehir's clerics are called Venomers and he draws many worshipers from the ranks of the Yuan-ti due to his like for snakes.

Neverwinter Nights 2: Storm of Zehir
The plot of this game surrounds Zehir's plan to take control of the chultan peninsula and the Sword Coast North. It describes his methods as aggressive, yet subtle. He likes his wishes carried out quietly, but boldly and does not forgive failure, though those who continue to please him can expect to be richly rewarded. He is confirmed as an interloper deity, though not where he is originally from, nor when he arrived on Toril.

In one of the last few scenarios of the game, the player characters defeat his herald, a powerfully-built giant yuan-ti abomination wearing an aztec-esque headdress, and then get the chance to converse with the deity, represented as two huge, red floating eyes set in scaly sockets and with feathery eyebrows. The voice that issues forth from this apparition is calm and confident. Despite the fact that this plan was ruined he reveals that it was but one of many schemes that he is sponsering all over the world.