This made me curious about what information about Primuses that is actually in the books, so I looked it up and made a list. Didn’t look thoroughly so might have missed something.
Bonisagus:
HoH TL: Holds considerable power and influence. Can command those of Cannophori rank to drop their research and do another task, can be overturned by the Colentes Arcanorum. Appoints the Tenentes Occultorum. Is Praeco of the Rhine and Grand tribunals. Appoints his successor. Can be relieved of duty by a unanimous Colentes Arcanorum.
Guernicus:
HoH TL: Very little information. Guernicus is ruled by the Magvillus Council which has two tiers. The Primus chairs these councils and sets the order of business. The Primus can be dismissed by the council.
Mercere:
HoH TL: Really no information.
Tremere:
HoH TL: The Primus rules the house. Can channel resources to projects. Appoints and dismisses the Exarchs and the Legatus.
Bjornaer:
HoH MC: House Bjornaer is ruled by the Bjornaer Council, not its primus. The Primus isn’t even the leader of the council unless he has a bear as a heartbeast.
Criamon:
HoH MC: The primas role is to support her house by managing mundane tasks and coordinating the house´s activities. She leads the Central Clutch and the council who rules the Cave of Twisting Shadows. Stays as a ghost, until the Enigma is solved, after being killed.
Merinita:
HoH MC: Really no information. The house is described as disorganized and contrary to each other.
Verditius:
HoH MC: The primus residence determines the house domus magna. It is the sole arbitrator for personal matters between house members. The house has no other structures so this is the only position of authority in the house. He can ask for advice, but final decision is his. Most decisions concern prize fixing and vendettas. His sphere of authority over his fellows is limited. His vote decides ties in the Contest.
Flambeu:
HoH Soc: Loose internal organization. No offices except Primus. Relatively few direct powers, rules more by persuasion than formal authority. Has the authority to preside over gauntlets, organizes the grand tournament. Nominally the leader for Castra Solis but the true power often lies elsewhere.
Jerbiton:
HoH Soc: The Primus has few formal powers. Sole authority to grant membership in the house and residence in Valnastium. May spend a portion of Valnastiums resources on personal projects. Also some ceremonial rights.
Tytalus:
HoH Soc: No information.
tLatL: Leads Fudarus and makes all decisions on ite behalf. Sets challenges for non-Tytalus that wishes to enter Fudarus.
Ex Miscellanea:
HoH Soc: Almost no house culture or organization at all. The primus decides membership in Cad Gadu. Sometimes has a Council of Four to help the primus guide the house.