oni

An oni is a type of yōkai, a class of supernatural beings in Japanese folklore. The term generally denotes a demon, ogre, or unclean spirit. Oni appearances and roles vary across regions and eras, and they have been incorporated into both religious cosmology and secular storytelling.

In traditional depictions, oni are large, humanoid creatures with horns, fierce faces, and fangs. They are often shown with red or blue skin and wild hair, wearing tiger-skin garments, and wielding a heavy iron club called a kanabō. Some variations depict hornless or more human-like beings. Despite their fearsome image, not all oni are uniformly malevolent in every tale; they can be antagonists, tricksters, protectors, or imprisoned beings depending on the story.

Oni appear in a wide range of folklore and literature. They are commonly portrayed as threats to humans and villages, though they also serve as symbols of chaos or the consequences of moral failings. Notable examples include Shuten-dōji, a legendary oni defeated by the hero Minamoto no Raikō and his retainers, and Namahage, ritual demon-figures in Akita Prefecture who visit homes during New Year to admonish laziness.

In Japanese culture, oni have influenced ceremonies, theatre, and modern media. The Setsubun festival popularizes driving demons away with the chant “Oni wa soto, fuku wa uchi.” Oni appear in Noh and Kabuki plays, as well as in contemporary manga, anime, and video games, where they may be portrayed as foes, allies, or cultural symbols.