 The oni reference Japanese mythology. In many Japanese tales  (including "Momotaro, the Peach Boy") Oni were analogous to demons,  and were known for committing horrific acts on humans. They were  described as having a horn or horns, being primitive and wearing  animal skins. In some myths, they also had control of the weather.  Male oni were hideous and violent, where as oni women were beautiful  but posessed of a fierce temper and jealousy.