This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Ningyo (Japanese)
Ningyo ("human fish") as the name suggests, is a creature with both human and fish-like features, described in various pieces of Japanese literature. Though often translated as "mermaid", the term is technically not gender-specific and may include the "mermen". The literal translation "human-fish" has also been applied.
Unlike the mermaids/mermen of the Atlantic Ocean and Mediterranean Sea, ningyo from the Pacific Ocean and the Sea of Japan are hideous to behold. Ningyo are more fish than human. They can have anything from ugly, deformed fish-like faces, to entire human torsos with long, bony fingers and sharp claws. Ningyo range in size from a human child to a large seal.