In Japanese folklore, an oni is the horned demon commonly shown with a club and tiger-skin loincloth.
Oni are supernatural beings in Japanese folklore, often translated as demons, ogres, or trolls. Traditional images show them as large, muscular figures with horns, fierce teeth, brightly colored skin, and an iron club called a kanabō. Their tiger-pelt loincloth is one of the visual features that makes the standard oni immediately recognizable.
Oni are associated with violence, cannibalism, storms, mountains, and the underworld. They appear as villains in tales such as Momotarō and in the legend of Shuten-dōji, one of Japan’s most famous oni. Their image is not always purely evil, however: oni figures can also serve protective roles, especially when displayed to ward off misfortune.
The annual Setsubun custom of throwing roasted soybeans and shouting “Demons out, luck in” symbolically drives oni away. Oni should not be confused with yūrei, which are ghosts, kappa, which are water-dwelling yokai, or tengu, birdlike mountain spirits. Individual oni may have names, but oni is the broader creature type.