The Story of Trundle
Trundle was the troll who was willing to do what trolls don't: he made a bargain with the Ice Witch Lissandra, offering his people's service to her agenda in exchange for a power she could provide. The power was real. The cost was that his tribe and eventually all trolls who followed him became increasingly corrupted — their flesh growing more dead-looking, their connection to the living world thinning — as the price of Lissandra's gift extracted itself over generations.
He rules as troll king with the particular authority of someone who is bigger, meaner, and more magically potent than any challenger. His ice club is both weapon and scepter. He hunts and fights with genuine skill, and he takes what he wants from the world with the directness of something that has made its peace with what it is and no longer spends energy on what it should be instead. He is a troll king. Troll kings take things.
The bargain's full implications are visible in his people, and whether he has considered what it means for their future is unclear. He operates in the present, which is a more comfortable frame for someone whose existence produces fewer questions than the long view would. He serves Lissandra's purposes. He also does exactly as he pleases. He has arranged for these two things to be mostly the same thing, which is the most sophisticated political maneuvering he performs.