As her name already suggests, the Demon Hag usually appears in the form of a shriveled old woman. She often is described as a maniacal, disheveled hag with wild-looking hair and an oversized mouth. In addition, she is sometimes depicted holding a kitchen knife or sitting next to a cooking pot. However, she is said to conceal her horrific appearance to put passers-by into a false sense of security, before attacking them and eating their flesh.
There are different versions of the story of how the Onibaba came into existence, but all of them involve the baby girl of a wealthy family in Kyoto. In one version, the otherwise happy and healthy five-year-old has not uttered a sound since birth. The worried family consulted many doctors without finding an answer to the girl's condition until they finally came upon a fortune teller. They were told that the cure was to feed the girl the fresh liver of a fetus, although, in a different version of the story, the cure was not a fetus' but a pregnant woman's liver. Either way, the gruesome task was given to the baby girl's nanny.
As she set off in search of a pregnant woman, the nanny left her own daughter behind, but not without leaving her with an amulet for protection, a so-called "omamori". The nanny's search went on for weeks and months. Tired and weary of travel, she decided to stay in a cave in Adachigahara to simply wait for a pregnant traveler to pass by. Years had passed when finally a lone pregnant woman approached the cave. Desperate, the nanny jumped the woman and used her knife to cut out the fetus' (or, depending on the version, the woman's) liver. It was only after finishing the task that she recognized the omamori she had given her daughter so many years ago. Driven insane by this realization, the nanny turned into a yokai and from then on attacked any person who would pass by her cave, and ate their flesh.
The woman on whom the story of the Demon Hag is based is said to have lived in a cave or a small house in Adachigahara and have died in a nearby place called Kurozuka. Adachigahara has a small museum that claims to hold her remains as well as the cooking pot and the knife she used to kill her victims.
