Tristan de Bois

"He blamed Uther and came to the gates of Camelot and challenged him. Uther won. But in his dying breath, Tristan cursed Camelot to one day suffer his return."

- Gaius Tristan de Bois, also known as "The Black Knight" was the brother of Ygraine and Agravaine de Bois, the brother-in-law of Uther Pendragon, and the uncle of Arthur. A former friend of Uther, he turned against him after the death of Ygraine. Many years after his death, he became the deceased uncle-in-law of Guinevere, the wife of his hated nephew, Arthur.

Early life
Presumed the eldest child of his parents, Tristan was closest to his siblings, Ygraine and Agravaine. When his sister Ygraine died at childbirth, Tristan blamed Uther for her death and challenged him to a duel. Uther won the duel but before he died, Tristan swore in his dying breaths that he would rise from the dead and avenge Ygraine.

Resurrection
Twenty-one years after his death, at Arthur's coming of age ceremony, Tristan was reanimated as a Wraith by the sorceress Nimueh. He crashed his horse through the window during the ceremony and challenged the knights to a fight to the death. Sir Owain took up the challenge and struck a would-be fatal blow, but ultimately died, Sir Pellinore took up the next challenge and also died, though he too struck a fatal blow. Arthur then challenged Tristan to a duel himself, and he accepted. Gaius and Geoffrey of Monmouth were able to identify Tristan by the crest on his shield. It is an image of a white Phoenix. He was the only knight known to have carried such a crest.

Merlin observed that both times the Knights fatally wounded Tristan, he lived. With the help of the Great Dragon, created a sword that can kill the dead. Although it was intended as a sword for Arthur's use only, it was Uther who fought Tristan with Excalibur. As a result, the Wraith died, and Tristan de Bois returned to the world of the dead, his revenge unfulfilled (Excalibur).