Jiemei

Jie Mei (ジエメイ, Jie Mei) was born in ancient China over 2000 years ago as the daughter of a blade-maker, and had a brother named Giryou. Their parents were murdered by Hakumen no Mono, and Jiemei overheard her brother speaking of a forbidden method to create holy blades: Human Sacrifice. Jiemei killed herself by throwing herself into the forge so that her brother could do this, and it drove him mad as he forged a blade and hammered it until his body became the shaft.

Jiemei is a spirit who appears from time to time to guide Ushio and his friends.