She is a member of the Tuatha Dé Danann and is known by the epithet Foltchaín ("beautiful hair"). She is the Goddess of the Woodlands, wild beaasts, and fertility. She owns herds of deer and cattle, and rides in a chariot drawn by deer. As goddess of domestic herds she had a magical cow of plenty and it was also known she had a power that enabled her to milk deer as if they were cows.
She was the wife of the legendary High King Adamair and the mother of 3 daughters named Fand, Be Chuille and Be Teite. 2 of these daughters were considered to be Witches, and one was a Faery Queen. Flidais was said to have a voracious sexual appetite, as did all of her daughters.
Flidais is a central figure in the Táin Bó Flidhais ("The Driving off of Flidais's Cattle"), an Ulster Cycle work, where she is the lover of Fergus mac Róich and the owner of a magical herd of cattle. The story, set in Erris, County Mayo tells how Fergus carried her and her cattle away from her husband, Ailill Finn.
During the Táin Bó Cúailnge (Cattle Raid of Cooley) she slept in the tent of Ailill mac Máta, king of Connacht, and every seven days her herd supplied milk for the entire army.
In Táin Bó Flidhais she has a favoured white cow known as "The Maol" which can feed 300 men from one night's milking.
Another Ulster Cycle tale says that it took seven women to satisfy Fergus, unless he could have Flidais. Her affair with Fergus is the subject of oral tradition in County Mayo.