Noppera-bo
Demons

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The noppera-bo, or faceless ghost, is a Japanese legendary creature. They are sometimes mistakenly referred to as a mujina, an old Japanese word for a badger or raccoon dog. Although the mujina can assume the form of others, Noppera-bo are usually humans. Such creatures were thought to sometimes transform themselves into noppera-bo in order to frighten humans. Noppera-bo are known primarily for frightening humans, but are usually otherwise harmless. They appear at first as ordinary human beings, sometimes impersonating someone familiar to the victim, before causing their features to disappear, leaving a blank, smooth sheet of skin where their face should be. Two famous stories about noppera-bo include:

The Noppera-bo and the Koi Pond

This tale recounts a lazy fisherman who decided to fish in the imperial koi ponds near the Heiankyo palace. Despite being warned by his wife about the pond being sacred ground and near a graveyard, the fisherman went anyway. He is met along the way by another fisherman who warns him about the same, which the initial fisherman decides to ignore. Once at the spot, he is met by a beautiful young woman who pleads with him to not fish in the pond. He ignores her, and to his horror, she wipes her face off. Rushing home to hide, he is confronted by what seems to be his wife, who chastises him for his wickedness before wiping off her facial features as well.

The Mujina of the Akasaka Road

The most famous story recollection of the noppera-bo comes from Lafcadio Hearn's book Kwaidan: Stories and Studies of Strange Things. The story of a man who travelled along the Akasaka road to Edo, he came across a young woman in a remote location near Kunizaka hill, crying and forlorn. After attempting to console the young woman and offer assistance, she turned to face him, startling him with the blank countenance of a faceless ghost. Frightened, the man proceeded down the road for some time, until he came across a soba vendor. Stopping to relax, the man told the vendor of his tale, only to recoil in horror as the soba vendor stroked his face, becoming a noppera-bo himself.

Relevance to Inuyasha

The "Un-Mother," that impersonates Inuyasha's mother in order to trap him is actually a noppera-bo.