I think the Matron Mother is intended for Great houses and other powerful Priestesses for lesser/minor houses I'd use Drow Priestess from the MM.
Menzoberranzan has 8 Matron Mothers on it's ruling council alone, and that isn't the only powerful house in the city. Still imagine 8 CR 20 Matron Mothers.
And that is one Drow city.
Menzoberranzan has 8 Matron Mothers on it's ruling council alone, and that isn't the only powerful house in the city. Still imagine 8 CR 20 Matron Mothers.
And that is one Drow city.