Morgana (played by Katie McGrath) is the ward of Uther Pendragon as Uther promised her father he would protect her after her father died. Arthur and Morgana care and look out for one another and they flirt and tease each other often. When Gwen states that not many women are born to be queens but some are, she is referring to Morgana and the royal court believes Morgana will one day be Arthur's Queen. Morgana is best friends with Gwen. According to Arthurian legend, Morgana was named Morgan Le Fay. She was often Arthur's healer. She was a witch, seer, shape-shifter, and the personage of Avalon. In Arthurian legends, after Camelot falls, it is Morgan Le Fay who takes Arthur to Avalon where they reside forever after.

Morgana disapproves of Uther's genocide against those who use magic and later in the series it is revealed that Morgana has the gift of prophecy through her dreams, and may unknowingly be a sorceress. However a sorceress is usually one who practices supernatural power through the aid of evil spirits, Morgana never uses magic with the aid of evil spirits. However, she is frightened of her dreams and often turns to Gaius for help to stop them. His potions fail to stop them and through these dreams Morgana has saved Arthur's life at least twice: she foresaw in a dream that he would be in danger when fighting Knight Valiant (and was able to throw a sword to Arthur when he lost his own) and later when Sophia would try to kill him. She also attempted to save his life in Series 1 finale, The Questing Beast, when she saw him attacked. He did not, however, heed her warning and was seriously wounded.