Everwinter is a frozen tundra wth few resource villages (rv). Part of the objective is to capture rv's as as many as possible. There is a limit on number of food/stone/wood rv's you can capture and they appear sporadically in random areas. They only increase production and you have to defend like conventional caste/outpost but you cant build. Attacking the Fortress can have ruby bonuses of 100+ for victories claimed.

The resource cost for Everwinter is 1/4 lost to and 3/4 from the region