Wendonai

Wendonai is a balor lord who, in -11500 was tasked by Lolth to seduce the Sethomiir clan, rulers of the Ilythiiri into her worship and grant them infernal magics. He succeeded and was probably the greatest (but by no means the only) influence on the fall of the dark elves.

After the "Descent", Wendonai continued his work, acting as advisor, tutor and sometimes consort to the most powerful Drow Matron Mothers. He tried to claim a little power for himself by leading a sucessful Drow and Duergar attack against the Elven Court in -4400 DR called the Dark Court Slaughter. Wendonai's efforts at personal growth over the next two millenia earned Lolth's ire as she had no intention to let the drow return to the surface. Lolth withdrew her favour of the demon in -2549 DR and the Matrons followed suit.

Wendonai then allied himself with Eltab, serving as The Hidden Layer's emissary to Faerûn for several centuries. In -623 DR though he was summoned by a Nar Demonbinder but was soon banished by an incredibly powerful cleric of Horus-Re for 2000 years. Those years were spent in 1377 DR and after two millenia of planning, set into motion his revenge against Mulhorand.