There was a topic on the Teslore subreddit asking us to invent a fun fact about anything in TES. I found the idea funny, so I decided to write about Udyrfryktes. And I thought I could also put the resulting fun fact here, so here it is.
Troll actually have some rudimentary religiosity.
Trolls klans frequently raid each other to kidnap females. Each klan constitutes its own harem, and the kidnappings allows to ensure genetic diversity without which the isolated klans would suffer from interbreeding.
When the various klans of a given area feel endangered or pressured by an external cause, or for other reasons, they can proceed to some ritual called the Mating.
Because of the frequent raids, klans distrust each other, and such a ritual is often difficult to organize. Therefore, when a Mating has to take place, klans send male homosixual Trolls to each other as Ambassadors-Shamans for the negociations - their lack of interest for females make them appear innocuous with respect to the other klans' harems.
For the Mating, each klan Patriarch sends the male Troll he considers the most worthy from a reproductive viewpoint - as humility isn't really praised among Trolls and as Patriarchs consider themselves to be the most worthy of their klan from any viewpoint, the Patriarchs most often come themselves. It can also occur that a male homosixual is sent, or one of the Patriarch's sons, when he has shown formidable strength or other desirable traits.
During the Mating, the elite Trolls, supposedly bearers of the best each klan has to offer, gather around the shamans in a circle, and bloody prayers are offered to some kind of animal deity of fertility. The Troll god then answers their prayers by granting his blessing to one of the present males, whose six is altered and who becomes an Udyrfrykte Matriarch.
The new Udyrfrykte Matron is then impregnated by the other present males, so she can give birth to a new bloodline of Udyrfryktes. Then, she moves on and tries to solve the problems encountered by the klans, which most often involves eliminating the threat and causing havoc.
Should the expedition prove successful, the Matriarch would be held in high esteem by the other klans. She would then be offered one male Troll from every klan involved in her creation to constitute her own harem, but the Udyrfrykte, together with her newly offered cicisbei, would be exiled, so they can found their own klan elsewhere. The resulting communities form the only example of matriarcal Troll klans we know so far.