Oni are raucous, defiant spirits of chaos and mischief. They can cause trouble for people but may also be protective. Some can be persuaded to become allies. Oni frequently enjoy a battle, so they may banish and disperse evil spirits and ghosts just for the fun of it, even without being asked.

Oni is frequently translated into English as “devil” or “ogre,” emphasizing their scary, destructive aspects. However unlike classic European ogres, Oni are not stupid or slow but very smart and thus formidable opponents with magical, supernatural powers. Allegedly if an Oni loses a limb, it reconnects and heals instantly—another reason why they so enjoy brawling.

Oni are spirits of justice who destroy as well as protect. They are often portrayed as vicious, malevolent, ominous Demons up to no good and are featured in many horror tales. Allegedly some enjoy the taste of human flesh. This legend of the human-eating Oni may derive from their origins as spirits of death.

Oni are pre-Buddhist spirits. There were originally both male and female Oni who supervised the frontier between life and death. (The disappearance of female Oni may account for some of the male Oni’s famed crankiness.) Oni were incorporated into Buddhism, becoming gate guardians of the various Buddhist hells and death realms. Their role now includes punishing sinners. Although spirits of death are rarely popular, Oni were perceived as fulfilling a spiritual function. Although considered dangerous, they were not evil and could serve as guardian spirits, if so inclined.

Without female Oni, reproduction must be otherwise accomplished. Although Oni were originally pure spirits, their ranks are supplemented by men who die while overwhelmed by excessive anger and are then transformed into Oni.

The Demonization of Oni began during the Kamakura era (circa 1185–1333 CE) with the rise of the new samurai class. Brawling Oni evolved into enemies of the samurai. A frequent theme of legends involves samurai foiling evil Oni. Oni became increasingly masculine and malevolent. True female Oni became rare; the Hannya, a horned female spirit, evolved into the Oni’s female counterpart.


Oni are shaggy, horned, fanged, tusked, and clawed with vividly red, blue, or black skin. Male Oni who wish to travel incognito may assume the guise of human women.


Onigawara roof tiles (sometimes translated as “gargoyle” or “Demon tiles”) are decorative, amuletic roof tiles, traditionally positioned at a roof’s highest, most prominent points. Onigawara traditionally incorporate images of Oni. By placing them on the roof, Oni are invoked to protect the home and residents. (Alternatively, their image is believed sufficiently ominous to keep malevolent spirits away.) Onigawara are now considered collector’s items; antiques are incredibly valuable.


Oni carry and wield the kanabo, a large spiked iron bar.


Datsueba; Enma; Hannya; Kings of Hell; Tengu; Wanyudo; Yokai


Encyclopedia of Spirits: The Ultimate Guide to the Magic of Fairies, Genies, Demons, Ghosts, Gods & Goddesses – Written by : Judika Illes Copyright © 2009 by Judika Illes.