Samebito

Samebito (鮫人, "shark men") are monsters found in Japanese folklore. They are humanoid for the most part with black skin and green, luminescent eyes. They usually sport a pointed beard, as well.

Samebito are the inhabitants of a vast underwater kingdom, so they have little contact with mankind. When a samebito does find itself on land, it is usually in some sort of trouble. They are honest creatures and will repay any kindness offered by a human being. In one story, for example, a samebito repays a debt by crying tears that transform into precious stones.