The ruin of a once grand beholder hive-city, Ooltul is now a large marketplace and residence of various wicked Underdark races who maintain an unsteady cease-fire. The party was directed here by Dooger T. Digger as a place where they might find information about the yuan-ti stronghold supposedly housing the crown of horns.
There, they spoke with the owner of the Skull Cap Tavern, a wizened mind flayer called Graa-kkak, who said he knew what they needed. The illithid wouldn’t part with the information unless the heroes eliminated a threat to him. The beholder crimelord Chk-kk also sought the crown of horns and would not take kindly if the mind flayer just up and told someone else.