In Brythonic mythology, an Asrai is a type of aquatic faerie similar in some ways to mermaids, nixies, selkies, sirens, or morgens. Some sources describe them as timid and shy, standing only between 2 and 4 feet tall, while others depict them as tall and lithe. They are said to look like beautiful young maidens, sometimes as young as children, while actually being hundreds of years old. They may have webbed hands and feet, resembling some descriptions of selkies
If an Asrai is seen by a man, her beauty is so great that, according to folklore, the man will instantly wish to capture her. The Asrai are as deathly afraid of capture as they are of the sun, for if captured or if even a single ray of sunlight touches them, it is said that they die and turn into a pool of water.
The tale told of one fisherman who caught an Asrai claims that the touch of her skin was so cold, that where the Asrai touched his arm while pleading for her freedom — and her life — the flesh has never been warm since.
Their inability to survive daylight is similar to that of the Scottish Fuath.