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-otoko (Japanese)
Yama-otoko is a monster found in many parts of Japan and described as half-naked and very hairy. He kidnappes people and if someone meets him in the forest and escapes, he usually gets ill. But gnerally the Mountain Man is a gentle monster, helps the woodworkers carry their loads in exchange for some food.
There is very little information about this kind of monster, however they are cannibalistic in nature and like to feed on human flesh. They appear to live in more rural areas and tend to avoid big cities.