Morgana

Morgana is the illegitimate daughter of Uther Pendragon, the second daughter and the youngest child of Vivienne, the paternal half-sister of Arthur, the younger maternal half-sister of Morgause and the adoptive daughter of Gorlois. Originally a kind-hearted individual, Morgana changed entirely, becoming evil after being corrupted by Morgause and being betrayed by her former-friend, Merlin. She subsequently turned against her family and friends, even helping to cause the death of her own father; she was ruthlessly determined to take over Camelot and allowed nothing to stand in her way