This is a novel that I read in early 90s, but I suspect was written well before then.
It occurs in modern times and there are multiple conspiracy groups in it. Each of these groups is referred to by an animal name, like the snakes or the badgers, by the person accompanying the protagonist, who is himself in one of the groups.
One of these groups is a group of mages, who prepare a spell, a weave, throughout the book. There are at least three groups; I believe there are four. I'm quite certain there's no more than five.
At the end of the book, the protagonist becomes part of all the groups at once. The one who had been accompanying him makes him their king, the wizards give him control of their weave after it went out of control, and a third group kidnaps him.