The Witherbark tribe split off from the Amani Empire after the Troll Wars and returned to their ancestral lands, in the areas that are now called the Hinterlands and the Arathi Highlands. Like all other forest trolls, the Witherbarks allied themselves with the Horde during the Second War under the leadership of Zul'jin, a famous troll hero from the Amani tribe. When the Horde was soundly defeated, Zul'jin disappeared, and the forest trolls abandoned their orcish allies.
The Witherbarks living in the Hinterlands have since happened across the Revantusks and launched many attacks against the small tribe, but the dwarves of Aerie Peak have also become a noticeable threat. In the meantime, the Witherbarks living in Arathi Highlands have grudgingly allied themselves with the Boulderfistogres in order to wipe out a far more hated enemy: the Horde forces who have constructed the settlement of Hammerfall.
The Witherbark worship a spider god, Shadra, whom they collect a very powerful venom from.