the diplomacy system could be applied to the members of my house, too. in-house diplomacy.
as the leader of my house I would have to give presents, influence, etc. to my fellow barbarians.
if i don't they might join other covenants, desert, revolt, try to assassinate me or one another, go renegade.
the other factions would try and bribe my people, lure them away.
so i need a lot of gold to keep my men happy and deal with the other houses.
when another house recruits a powerful new member, i can try and bribe him into my own services or turn them into spies and traitors... lots of fun to be had, surely.