In Peredur, a pack of nine witches who lived with their father and mother.
They killed one of Peredur’s cousins and maimed an uncle. Peredur saw the head of his slain cousin on a platter (this cousin corresponds to the murdered Goondesert in the Third Continuation of Chrétien’s Perceval), and he learned that he was fated to destroy the Hags for these actions.
Peredur was eventually led to their lair by another cousin in disguise, and he killed the Hags with the help of Arthur’s other warriors.
See also
Percivale | The Legend of King Arthur
Sources
Pa gur yv y porthaur | Poem 31 of the Black Book of Carmarthen, probably c. 1100
Peredur | 13th century