Morgause

The Queen of Orkney, today best known as Morgause /mɔːrˈɡeɪz/ and also known as Morgawse and other spellings and names, is a character in Arthurian legend in which she is the mother of Gawain and Mordred, both key players in the story of King Arthur and his downfall. In early texts, Mordred's father is her husband, King Lot of Orkney, with whom she may also have various other children. In later versions, including the seminal Le Morte d'Arthur, Mordred is the offspring of Arthur's accidental incest with Morgause, his estranged half-sister. There, she is furthermore a sister of Morgan le Fay, as well as the mother of Gareth, Agravain, and Gaheris, the last of whom murders her.