Oni no Fuhinko

Oni no Fuhinko was an oni of the Shadowlands, a demon that fed on and enhances dark desires. Everyone who looked at the Oni would think the Oni was looking right at him; and it was. It was impossible to see the back of a Fuhinko's head.

Ryoko Owari
In the guise of "Auntie Bohaku", she posed as the proprietess of the House of the Plum Blossom at Ryoko Owari Toshi, frequented only by those with especially jaded and perverse tastes. She was a friendly woman of indeterminate age, known for her attention to her clients. Secretly run for its benefit, the Plum Blossom clientele required special attention indeed. Their most unacceptable urges could be gratified, for Oni no Fuhinko feed off of the excesses of those who gave in to their basest desires. Those who indulge were rewarded with heightened pleasure - and the only price was the hidden cost to their souls. Bohaku's geisha were terrible women of pleasure armed with implements of torture: hairpins, small knives, and other, more specialized tools. The oni was eventually uncovered by a group of samurai who took care of the demon.

Hand of Fuhinko
Through long proximity to Fuhinko, her fan became a nemuranai, named the Hand of Fuhinko. Anyone who opened the fan appears to be facing all directions and could dimly sense if anyone was looking at him.