This clan is not great. While every clan in Northgard is unique and this one certainly feels different from all the others, there are some serious balancing issues here.
The mechanics of the clan require you to sacrifice units every few minutes for minor buffs or suffer major penalties. This means that you are either sacrificing villagers which slows down your build up or you are constantly buying thralls to sacrifice which slows down your gold accumulation.
Neither of these options makes for a very fun play experience and the payoff for what you get doesn't feel worth it.