The Babadook

A tribe of barbarians in the Northern Wastes.  They are known for riding war mammoths into battle, used to crush and terrify their foes, and more recently, smash through defensive fortifications of the Imperial army.  Due to their military might the Babadook have maintained their independence, but as more of the neighboring tribes are either conquered by the Hadrians or choose to join their alliance the Babadook find themselves increasingly isolated.  
While the elders of the tribe argue amongst themselves about the path forward, an increasingly large number of young Babadook have left the tribal lands, either heading to Korribon to join the legion or strike it out on their own as adventurers.