Asara's pact
She says Lolth relies on the network of war and conquest she has built up. Without that, she is nothing but a mortal. The drow act as a machine to keep her alive, and powerful. To truly kill her, her network needs to be destroyed. She will only continue to grow in power. She may become nigh unkillable if she can take down Greyhawk. We need to find her sanctum.
It is known as the Demonweb Pits. Going there requires a full plunge beyond the under dark. Ideally, they need to pass through via chasms in the earth.
She will ask anyone to exchange magic.