Mother-in-law of Bredbeddle, the Green Knight in The Grene Knight. Her daughter loved Gawain, so she provided her son-in-law with the magic to lure Gawain to his castle.
She takes the place of Morgan Le Fay from Sir Gawain and the Green Knight.
See also
Gawain and the Green Knight | The Legend of King Arthur
Source
The Grene Knight | c. 1500