The provided subject description identifies Oni as a city in Indonesia; however, the source material clarifies that an oni is actually a type of yōkai, demon, orc, ogre, or troll originating from Japanese folklore. These creatures are traditionally believed to reside in caves, deep within mountains, or in hell.
Oni are characterized by their superhuman strength and associations with thunder and lightning. They are often depicted as hulking figures with one or more horns, massive teeth, and sometimes a third eye on the forehead. Their skin is typically colored red, blue, black, or yellow, and they are frequently shown wearing tiger-pelt loincloths while carrying iron kanabō clubs.
While predominantly male in history, oni can be female, with some referred to as Yamauba. They possess the ability to change their appearance to deceive victims and have three to six digits on their hands and feet tipped with claws. Despite their reputation for murder and cannibalism, they are also occasionally linked to bringing wealth and good fortune.