Broken Skull Guardians are trolls, the land guards for Dulak's Harbor. They seem to be the only wandering mobs in the zone. Their patrol route takes them up and down the middle of the streets of the harbor, and they frequently stop at different stations on their path. If you find one of the safe hidey holes in the city to make camp in, you can pull the guardians back in them to fight with little fear of interference.
In about 15 kills, I've seen 2 compass notations and 1 insignia drop, in addition to the usual Broken Skull loot - various Zraxthil forged weapons, bucklers of Innoruuk and yummy troll parts.