Seven Kingdoms: Seowyn's Crossing
The githyanki are one of two races descended from an unknown proto-race native to Tol. At some point in the past, their ancestors were captured and taken by the illithids to the Far Realm. After the rebellion of Gith Devnara, the proto-race returned to Tol, butthey found they could not settle there. Instead, they split into two factions. While the other race, the Githzerai, traveled to the Elemental Chaos to study the fighting style they had learned from the Kalashtar spirits in the Far Realm, the githyanki went to the Astral Sea in order to seek spiritual enlightenment. Instead, they found the corpse of the Mourned God.
Dismayed to discover that even the Gods could be killed, they embraced a darker side. Fashioned a city from the bones of the Mourned God, their capital city of Tu’narath is ruled by the undead wizard queen Vlaakith.