As the “Washer at the Ford” she wanders near deserted streams where she washes the blood from the grave-clothes of those who are about to die. It is said that mnathan nighe (the plural of bean nighe) are the spirits of women who died giving birth and are doomed to do this work until the day their lives would have normally ended.
In the ancient Celtic epic, The Ulster Cycle, The Morrígan is seen in the role of a bean nighe. When the hero Cúchulainn rides out to war, he encounters the Morrígan as a hag washing his bloody armour in a ford. From this omen he realizes this battle will be his last.
A bean nighe is described in some tales as having one nostril, one big protruding tooth, webbed feet and long hanging breasts, and to be dressed in green. A mortal who is bold enough to sneak up to her while she is washing and suck her breast can claim to be her foster child. The mortal can then gain a wish from her. If a mortal passing by asks politely, she will tell the names of the chosen that are going to die. While generally appearing as a hag, she can also manifest as a beautiful young woman when it suits her, much as does her Irish counterpart the bean sídhe.