A Quimbanda terreiro is headed by an initiated person holding the title Tata if a man and Mae if a woman. The role combines two things that are often separated elsewhere: ritual authority within the house, and practical service to people who come to it with problems.
On the ritual side, the head opens and closes ceremonies, holds the standing to authorise the work of other mediums in the house, and carries the relationship with the particular Exu or Pomba Gira the house works with. On the service side, Quimbanda is consulted for concrete results in matters of money, law, love and protection, and the Tata or Mae is the person a client deals with to have a spirit's help engaged on their behalf.
The two sides are not in tension in the way an outside observer might expect. A tradition that understands its spirits as bound by obligation and reciprocity requires someone who can hold up the house's end of that relationship, and the authority to conduct rites and the capacity to get results are the same capacity described from two directions. Kelly Hayes's ethnographic work on Pomba Gira devotion in Brazil describes how this looks in the running of an actual house.
The titles themselves carry the tradition's Central African inheritance. Tata is a Kikongo and wider Bantu term of respect for a father or an elder, and it appears as a title of religious seniority across the Afro Brazilian traditions whose ritual vocabulary descends from that region, distinguishing them from the Yoruba derived titles used in Candomble houses of other nations.