The warriors of Halas are otherwise known as the Wolves of the North under the leadership of Kylan O'Danos. They are opposed to the Rogues of the White Rose, the rogues of Halas. The Wolves of the North support the Merchants of Halas and the Steel Warriors of Freeport and Qeynos.
Be warned that doing quests for the Warriors guild will lower your faction with the Rogues and that the Banker in Halas is a member of the Rogues Guild. Turning in Blackburrow Gnoll Fangs to Lysbith McNaff is the normal way to raise faction with the Wolves of the North, but at the cost of Rogue faction.