In Japanese folklore, a red-faced, horned ogre often carrying a club is an oni.
Oni are supernatural beings classified as yōkai and commonly translated as demons, ogres, or trolls. Traditional depictions show them as large, fierce figures with horns, prominent teeth, brightly colored skin, and an iron club called a kanabō. Red is especially familiar, although oni may also be blue, black, or yellow.
Their imagery is closely connected with Buddhist and folk ideas about hell, punishment, and malevolent spirits. Stories place oni in mountains, caves, or the underworld, where they may torment sinners. They are also associated with violence, cannibalism, thunder, and supernatural strength.
The annual Setsubun custom gives the creature a less frightening role: people throw roasted soybeans while shouting “Oni wa soto, fuku wa uchi,” meaning “Demons out, fortune in.” Oni should not be confused with kappa, aquatic yōkai; tengu, mountain-associated supernatural beings; or yūrei, the ghosts of the dead.