The Undead Horde
They're a horde...of undead...that about sums it up.
This mob of flesh consist of several types of undead:
Released from bondage when the soul of Aseun was awoken, demons called forth the tortured souls in their realms and retured them to the rotting bodies, corpses and skeletons that once housed them in life. The undead arose, killing all in thier path. A path in a disturbingly structural manner.
Masses of risen dead that swarm by the thousands. Attacking villages, towns and cities. Led by an unknown entity, fearsome leaders are chosen to lead them, with instruction for chaos.
One known horde was defeated at the village of Rell, the remnants of the army dispersed, small bands roaming the countryside.