Oni are the viable offspring of a pairing between Human and Ch'Karn.

Though this rarely occurs, there are self sustaining populations in the mountains of the Winterlands. Such pairings usually kill a human mother in childbirth. They are about 8-9 feet tall, heavily built, retaining their Ch'karn parent's antlers, body hair and sharp teeth, with their human parent's basic skeletal structure, forward jointed legs and padded feet.