Her characteristics vary depending on the locality, and differing traditions ascribe to her the powers of imparting knowledge or the granting of wishes if she is approached with caution.
It is said that mnathan-nighe (the plural of bean-nighe) are the spirits of women who died giving birth and are doomed to perform their tasks until the day their lives would have normally ended.
A maiden from Cromarty was walking along a path by the side of this loch one Sabbath morning, and after turning a corner she saw a tall woman standing in the water "knocking claes" (clothes) on a stone with a bludgeon.
Shortly following the appearance of this figure, the roof of Fearn Abbey collapsed during worship service, burying the congregation in debris and killing thirty-six people.
II, runs as follows: In the dead watch of the night, ‘Gille-cas-fliuch’, Wet-foot Man, of Great Clanranald of the Isles, was going home to Dun-buidhe in the upland of Benbecula— ben of the fords.
And when he was westering the loch, whom should he see before him in the vista on the ‘clachan’, stepping stones, but the washer woman of the ford, washing and rinsing, moaning and lamenting— Gille-cas-fliuch went gently and quietly behind ‘nigheag’ and seized her in his hand.
“Let me go,” said nigheag, “and give me the freedom of my feet, and that the breeze of reek coming from thy grizzled tawny beard is a-near putting a stop to the breath of my throat.
Much more would my nose prefer, and much rather would my heart desire, the air of the fragrant incense of the mist of the mountains.” “I will not allow thee away,” said Gille-cas-fluich, “‘till thou promise my me three choice desires.” “Let me hear them, ill man,” said nigheag.
A cow was felled accordingly, and a little coracle was constructed, in which Clanranald went from the island over the loch to the mainland, and he never again returned Dun-buidhe in the upland on Benbecula.’A bean-nighe ('washerwoman') is a specific type of ban-sìth.