In another life centuries ago Owaranai was a man, a skilled swordsman raised in a brutal dojo with no parents, only taught the way of the sword and naught else. He had no family, and no spirits to watch over or guide him. When he came of age that the dojo’s owner felt he could do battle, the boy was set loose on the world in pursuit of demonic incursions across Uikku. He became a great swordsman and was feared by all Oni, but still he found no love nor appreciation for his exceptional work from his masters.
One day he finally met his match, bested by an Oni infinitely more powerful than he could ever dream of beating in his mortal coil, but this demon offered the boy a chance: drink some of the demon’s blood and become reborn as one himself, finding a place of camaraderie among the Oni who had so greatly become to fear and respect him. So he took the opportunity, leaving his humanity behind as his form twisted and contorted. Now he is one of the most powerful Oni to walk the lands of Yomi, the Underworld beneath Uikku. From there he has bided his time, wishing one day a chance to return to the surface world permanently and have it be a land both spirits and mortals can share.
But his perception of mortals sees them as well beneath him, and he wishes for a place where any weaker than him would be his servant. In his many centuries as a demon he has often challenged powerful Samurai to duels, and none could best him. Only in times he has been greatly outnumbered has Owaranai Oni fallen, and when that happens it takes him only a few days to return again.