This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Nekomata (Japanese)
Since the Edo period, it has become generally believed that domestic cats turn into nekomata as they grow old, and mountainous nekomata have come to be interpreted as cats that have run away to live in the mountains. As a result, throughout Japan a folk belief developed that cats should not be kept for long periods.
Yoshida Kenko stated that a nekomata exists deep in the mountains that feeds on human flesh. It was also around this time that Fujiwara Sadaie mentioned the existence of nekomata in his scroll called Meigetsuki or The Record of the Clear Moon, also known as the Diary of the Clear Moon.