The frontier is an irradiated wasteland that covers most of the kingdom of Amantia. No one knows what created it, but it has been in place since long before humanity resurfaced.
Many species of monster call this land home. The dinosaurs known as stone runs hide in the mountains, sephies feed on the radiation, and feroraptors provide an ample food source for those who try to survive here. While rare, there are reports of wandering automata, relics of a forgotten age.
While most of the frontier is uninhabitable, there are regions where small towns and villages eek out a living. They rely on trade, and many frontiersmen turn to banditry to provide for their families.