Bae is a The Noppera-bō or faceless ghost. They are Japanese yōkais that look like a human but have no face. 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 the other, noppera-bō are usually disguised as humans. Such creatures were thought to sometimes transform themselves into noppera-bō in order to frighten humans. Lafcadio Hearn used the animals' name as the title of his story about faceless monsters, probably resulting in the misused terminology.

Noppera-bō 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.

Bae, however, became a Noppera-bo by mistake. She has spent thousands of years trying to correct this mistake. She learned that if she can talk to a seance or a medium, the medium can help her track the spirit that turned her into a Nopera-bo. That's how she found Khan, a pure-hearted monk who has the heart to help anyone in need. She tried talking to him but miscalculated and ended up possessin him, instead.