Eberron - Dreams of Xen'drik
Years ago, an army of Drow led by Melraevel Pilar’kah entered the desert, following rumors of a great power hidden beneath the mountains to the north. They spent a great deal of time searching the mountains and the underground tunnels beneath it, even excavating their own short-term residences there. When they discovered that the hidden power was nothing less than an imprisoned rakshasa rajah, Melraevel withdrew her forces as quickly as possible and left the desert. Ilivolin, however, fell under the demon’s sway and sold her soul to it in exchange for power. Many of the drow following her did so as well, but the imprisoned fiend demanded more – he commanded Ilivolin to hunt down her former mistress and sacrifice her, in exchange for even greater power.
Before Ilivolin and her forces could truly muster their power and leave the frozen caverns, a group of adventurers found thier way below, hoping to gain the Drow’s aid against Montu Chezzak. They slew Ilivolin and several of her people, and barely escaped with their lives.