This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Yama-uba (Japanese)
The creature had origins in the town of Masaeki, Nishimorokata District, Miyazaki Prefecture, and there is a tale that the "yamahime" would appear as a woman around twenty years of age and would have beautiful features, a small sleeve, and black hair, and that when a hunter encounters her and tries to shoot at it with a gun, she would repel the bullet with her hands.
In Hokkaido, Shikoku, and the southern parts of Kyushu, there is also a yamajijii and the yamauba would also appear together with a yamawaro, and here the yamauba would be called "yamahaha" and the yamajijii a "yamachichi". In Iwata District, Shizuoka Prefecture, the "yamababa" that would come and rest at a certain house was a gentle woman that wore clothes made of a tree's bark.