I'd say you run these guys as the mafia. It's a group that is led by a secretive ruling council, but they have false figureheads put into place so if anyone wishes to move against them, the figureheads may get whacked, but the ruling council lives on. The abhor open conflict, preferring to get their means by soft force (extortion, blackmail, etc). Due to those methods, a lot of their work is collecting information that could later be used as leverage. Like street gangs, they have tiers of membership, and new members need to prove themselves by taking on some menial jobs that put them in high risk situations. That makes the junior members the thugs. Elder members take on jobs that manage the flow of goods, move money around and work their way into the ruling class, examples:dafelsheim wrote: 7. More information on the Red Rat Clan! What exactly are their goals and methods? Are they still after Rolf? How do they interact with Magnus? Is Knutt a member? What is the nature of their relationship with Gunnar?
- A merchant who has vessels at their disposal along with trade routes
- A tavern-keep that can collect info about the town from the patrons and can accept cash that needs to be moved from person to person
- An advisor to a king who can use some of the king's influence to get jobs done
So specifically how they relate to each character:
Fjalar: I have his as a member of the Red Rat clan
Grimm: Certain trophies can fetch a handsome price overseas, so they check in on him to see if they can buy any rare hunted monster heads
Gunnar: sells his excess wares to the clan
Hakon: he hates the clan, but tolerates them since they act as enforcers for him when he needs something done "off the books". They have a tenuous "truce"
Halfdan: is oblivious to their existence
Ingvar: he's heard of them, but hasn't had any interactions with them (as far as he knows)
Ivar: Ivar uses the red rat clan members for income and information
Jadvyg: the clan stay away from her
Knut is a member, but is in the clan only for his own betterment. He has no desire to increase his membership level, and is happy to keep his hands in both his own business and in Red Rat clan business.
Magnus: he knows a lot of the members and often does business with them. He sees them as a valuable tool. The clan also sees Magnus as the most powerful figure in Evingard and want to keep cozy relationships with him.
Rolf: they are looking for Fingers and have a hit out on him
Sven: he is mildly aware of their presence and for some reason, the Red Rats like Sven a lot and don't bother him.
Thorlaug: the clan avoid this fella
Ulfeid: He is a member and membership helps him indulge in his vices. The clan also has clear leverage on him and control him to a great degree.
I also had the Red Rat clan involved in the fresh raspberry trade between Ivar and Sven!

Enjoy!