OK, he's rather unusually scaled figure. He seems to be about halfway between minifig and Miniland scale. He's standing up straight, which is unusual in a troll, but maybe he's just at attention. I mixed all 4 greys to give him a stony, mottled look. But enough talking, here he is.(Whole set)
Have you read the Art of Discworld book? I think it would do wonders in refining your model. That said, peicemaker is done well, and I instantly recognized the bundle of spears.