An ogre (oni) mother once gave birth to a child who looked human. Rather than an ogre's horn, the child was born holding a sword named "Onikirimaru," or Ogre Slayer. He has no name and is referred to only by the name of his sword. Although he appears human, he is pure ogre. Believing he will become human once all of his kind have vanished from the human world, he sets out on his destiny to slay all of his kind. Even now, in the mother world of Japan, he is still out there slaying ogres.