Oni are descendants of the anger, hatred, and scorn of Izanami, vessels of impetuous, simmering power that manifests across generations. Saturated in magic, Oni innately command primal, supernatural forces. An Oni's retort may physically scold the body of a foe, flesh might reknit under their palms in moments of compassion, or they may physically shrink when gripped with terror.
In nursery rhymes, Oni are fearsome bogeymen that haunt the nightmares of children and adults alike, yet they are very real and always hungry. They find human babies, especially, delicious. Oni look like demonic ogres with red, blue, or green skin, dark hair, canine-like fangs extending from the top and bottom rows of teeth, and a pair of short ivory horns protruding from their foreheads. Their eyes are dark with strikingly white pupils, and their teeth and claws are jet black.
Night Haunters. By the light of day, an Oni hides its true form with magic, gaining the trust of those it intends to betray when darkness descends. These creatures can change their size as well as their shape, appearing as humanoids as they pass through towns , pretending to be travelers, woodcutters, or frontier folk. In such a form, an Oni takes stock kof the selection of humanoids in a settlement and devises ways to abduct and devour some of them.
Magical Ogres. Oni are sometimes called ogre mages because of their innate magical ability. Though they are only distantly related to true ogres, they share the ogres' habit of joining forces with other evil creatures. An Oni serves a master if doing so proves lucrative or provides it with a luxurious, well-defended home. Oni covet magic, and they work for evil wizards and hags in exchange for useful magic items.