Oni cosplay refers to dressing up as an “Oni”, a type of demon or ogre from Japanese folklore, commonly featured in many anime, manga, and games. In cosplay, this means wearing costumes that reflect the traditional or stylized anime versions of Oni, which often include horns, sharp teeth, red or blue skin, and warrior-like clothing.

In Japanese mythology, an Oni (鬼) is a supernatural creature, usually large, fearsome, and horned, often associated with punishment or chaos. In anime, Oni are sometimes portrayed as villains, but can also be funny, tragic, or even heroic characters.