Icelandic trolls can´t be categorized as a precise whole so we do have a few versions to represent them in the game. One of these are the Rock trolls
Rock trolls in Island of Winds
Rock trolls can move beneath mountain and hill, but can only enter the overworld through stone surfaces that represent points of contact with the underground. Such places of power are usually recognizable by a higher number of troll faces in the rocks, at least to those who know how and where to look.
Each rocky region is ruled over by a master troll and in the Gorge, that troll goes by the name of Skolli. Rock trolls are reclusive creatures and seeing one out and about is a rare occurrence. Some say a troll sighting brings luck; others deem it an omen of ill tidings. Legend has it that when many trolls go on the march, a great calamity is imminent. But be reminded the trolls are not at fault. There are different and more evil powers at work on the island.