Grymkins
The Grymkin are the denizens of the wilderness of Urcaen beyond the protection of the gods. They are not undead, or demons, but have both souls and physical bodies, and warbeasts are the nightmares of the Defiers given flesh and blood.
Grymkin tormented the defiers before they learned to control them. The Defiers themselves are five humans who were banished to the wilds of Urcaen for refusing Menoth's law. Their wills were so strong that they each became demigods dedicated to opposing Menoth and punishing his creation, which they see as corrupt and wicked.
If Infernals ever invaded Caen in full force, it would mean the end of the world and the eternal torment of all living souls. The Grymkin, then, are the world's twisted salvation from annihilation.