Geirildin Sethomiir was the coronal of the illythiiri house Sethomiir. He was a dark elf and powerful mage during the time of the Crown Wars. He summoned the balor Wendonai in -11500 DR to help him against the Aryvandaari and to help him achieving a leading position among the other dark elven clans. Ultimatly this drove the dark elves into the arms of Lolth and was one of the causes for their socalled Descent.