Encyclopedia Entry
A kind of arachne that only inhabits the Zipangu Region. They possess the upper body of a woman with green skin, and the lower body of a spider covered in black hair. They’re one of the monsters feared as “monstrosities” in Zipangu. Even among monsters, their nature is especially ferocious. Tainted with immense desire, thoughts of savagely raping and violating men are always on their mind. So great is their lust that their body is always hotly seething.
Normally they live deep in the mountains, but sometimes ushi-oni come down from the mountains and attack human settlements seeking men. At that time, if they find a man who strikes their fancy, they’ll shoot out webbing that is almost like a rope, tie him up, and take him back home deep in the mountains. Then, as if to unleash all the bestial lust that had built up until then, they’ll rape the man and indulge in essence. No matter how much sex they have, their boundless sexual lust is never satisfied. They never get tired in the middle of sex, and they will keep thrusting their hips against a man relentlessly.
Once they’ve gotten a hold of a man, they never show themselves around humans again, secluding themselves in their nests deep in the mountains. They end up spending most of the day doing nothing but violating their beloved man.
Their blood is thick with mamono mana. Sometimes humans appear who try to slay these “monstrosities,” but those who cut them are always bathed in their blood as a result. Those who have been bathed in this blood are twisted by the high concentration of mamono mana. If it is a human man, then he’ll soon change into an incubus whose mind is all but consumed with screwing monsters. If it’s a human woman, then she’ll end up becoming an “ushi-oni” herself.
When a woman transforms into an ushi-oni, the great transformation is not only external, but internal. No matter how docile her former personality was, it will change into an extremely aggressive personality like that of the ushi-oni. The bestial desire to rape men and corrupt them with their own hands boils up. The bestial lust causes her body to begin to hotly seethe as though boiling, and she becomes unable to think about anything but raping men. And then, guided by bestial lust as a new “monstrosity,” she’ll head for a human settlement to get a man.
Additionally, the resilient body of an ushi-oni soon regenerates after being wounded. On top of that, they don’t even appear to feel any pain from minor wounds. They aren’t at all disturbed by the intruders who go after them. It is even said that they ignore the intruder before and after they’re cut, continuing to violate their man.