Eastern Oni are a dangerous variety of Youkai which resemble enormous, muscular humanoids with horns and either blue or red skin. Aside from being absurdly strong, these creatures are also nearly impossible to kill, having an inhuman resistance to damage and regenerative abilities. It is said that an Oni’s skin is so thick that it cannot be harmed by normal weapons, and can slay any amount of mundane troops in combat, no matter how outnumbered the beast may be.
Oni are, however, vulnerable to magical attacks and can be banished by the abilities of an onmyouji. Upon the appearance of an Eastern Oni, the local temple will often launch a full-scale operation, deploying all of the priests at their command in order to locate and banish the creature as soon as possible before it can begin a rampage.
Eastern Oni are known to be incredibly stupid, possessing the intelligence of a rabid animal despite their humanoid appearance. They appear to have no motivations beyond seeking violence and destruction. This is in contrast to Western Oni, which are known to be more civilized in their customs.
The color of an Oni’s skin links it to an element. Red-skinned Oni have an affinity for and are resistant to fire, while blue-skinned Oni are tied to the element of lightning. It is said that powerful Oni can summon their associated element and wreath their weapon in it, increasing even further their potential for devastation.
Western Oni are more common, but less understood by the general public. When an unlearned individual speaks of “Oni”, it is usually Eastern Oni to which they refer.