 Illithids typically dwell in dim, underground settlements, usually in the Underdark.Perhaps the best-known illithid settlement on Oerth is the city of Dra-Mur-Shou, located within several miles of the Vault of the Drow.A number of illithids also make their home in the drow city of Erelhei-Cinlu, due to the presence of a well-known mind flayer research center.