As an example, I submit Viking Trolls.
Viking Trolls (actual name unknown at this time) live on the far east coast of Iceholt, at least as far north as the Frozen Mountain Trolls. They broke off from Guttlekraw long ago and now have a cold, salty settlement on the coastline, braving the seas.
There is a small human settlement south of them that don't really like them all that much (think of Gotara Tribe but afraid of green sea-beasts riding boats). The Trolls don't associate with them if they can get away with it.
So, as far as the game is concerned, this would add:
A Viking Troll character template and associated graphics for Male, Female, and Child.
A cold weather, Coastal version of the Human template and assoc.
Boats (need them for wavedancers anyway)
Cold sea creatures