Encyclopedia Entry:
A monster distinguished by the horns growing out of its forehead, and its namesake blue skin. A type of ogre called “oni” that only inhabits the Zipangu region. Like all oni, they have a fierce disposition, and extraordinary strength. They’re feared by humans as monsters, but they’re actually quite intelligent and rational. They also have a calm side to themselves which is very atypical for an oni, and for that reason, unlike other oni, they don’t randomly assault human men. They can often be seen hanging around other oni such as “red oni,” etc. Because of their disposition, they often serve as the brain of the group, controlling the rest of the oni and restraining their emotional and coercive actions.