These creatures are foul things that prey on the weakness of loss. Their home society, and indeed, their home, in completely unknown, as all that have been found have been killed to out standards.
The hammer of a war-god avatar, this massive weapon must be wielded by a giant or other supernaturally strong being. When struck against the ground, a massive seismic wave will propagate outward from the wielder subjecting all in its wake to a massive earthquake. This quake is strong enough to shatter castle walls.