Orlassk

Orlassk, the Lord of Stone
''The daelkyr are creatures of madness. A daelkyr drives mundane creatures mad with its presence, and it twists and corrupts everything that it touches. But not all daelkyr are alike. The greatest of the lords of Xoriat have their own specialties and unique powers.''

''Orlasskis the master of stone. Stories credit this daelkyr with the creation of the medusas, basilisks, and all other creatures with the power to turn flesh to stone. The medusas of Droaam deny having any ties to the daelkyr, and they are not aberrations. But the records of the Gatekeepers clearly show that medusas fought on the side of the daelkyr in the battle for Cazhaak Draal; whether they were creations of Orlassk or simply its slaves is open to debate. Orlassk's citadel is said to be formed of living stone -- a giant gargoyle that prowls the depths of Khyber.'' (PnP lore)

Orlassk is featured in multiple quests with Xoriat / Madness flavor, often competing with his rival, Belashyrra:
 * Reign of Madness quest chain
 * Heart of Madness quest chain