Crannogman Bog Devils
A soldier's life is one of constant danger, particularly in the Neck's swampy terrain. Some of the most feared ambush soldiers in all of Westeros are the Crannogman Bog Devils.
Vassals of the Reed family, they're adept at blending in with swampy terrain, using their light armor to keep from being bogged down and dealing swift death with their poisoned tridents. The merest prick from their weapons causes agonizing wounds and a painful demise. The Bog Devils then simply melt away among the trees and brackish water, leaving nothing but the dead and the groans of the dying.