The One Ring: The Nameless Fellowship
Three nature-spirits, called the River-Maidens, dwell in the Black Tarn. One is seen most often in the fast-flowing upper part of the Dusky River. She is the youngest of the three, and the most shy. Only rarely does she appear, and only to children or those who are especially kind or in need. Silverbell is her name. A second maiden is encountered frequently in the middle section of the river. She is a friend to the Woodmen, sometimes guiding their boats past danger, or making merry with them — and it is said that some Woodmen are descended from her dalliances. Her name among mortals is Sunshadow. The third maiden is seen only in the vicinity of the Black Tarn. She is the eldest of the three, and the wisest. She brings the Woodmen tidings of danger; when Spiders creep around the lake, or the Werewolf roams close, the maiden of the lake may warn the fisher-folk of their peril. Her name is rarely spoken aloud — it is Duskwater in the tongues of Men.
All three River-maidens usually appear as young women swimming just below the surface of the water, but they all may assume the shape of silver trouts, to best flee from a threat.