Gorlois

Sir Gorlois Le Fay was Uther Pendragon's best friend and the husband of Vivienne.

Family Life
Gorlois was married to Vivienne, and held a high position in the court of Camelot. Due to his position, he was a close friend of the King Uther Pendragon. At some point Gorlois was away from his home for a long time, during which, unknown to him, Vivienne and Uther had an affair, resulting in Morgana being conceived. Gorlois raised Morgana, though it is unknown whether he knew of her true parentage.

It is likely Gorlois is the father of Morgause, the evidence for this being that Morgause wore a bracelet that bore the symbol of Gorlois' house, which she later gave to her (then thought) half-sister Morgana. For reasons unknown, Gaius was asked to smuggle her out of Camelot after she was born and give her to the high priestesses of the Old Religion. Uther was led to believe that Morgause had died shortly after her birth.

Death and Aftermath
According to Morgana, Uther sent Gorlois into battle and promised him reinforcements. However Uther failed to send the reinforcements, resulting in Gorlois' death. Uther promised Gorlois that he would look after Morgana and subsequently readopted her as his own daughter. Maybe Uther didn't sent the reinforcements because he was afraid thet Gorlois could know/learn about Morganas true prentage.

Gorlois's resting place is near the Darkling Woods which is just outside the citadel of the palace. It is on a hill where a special stone has been placed for him.

When Morgana and Morgause conquered Camelot, they replaced the Pendragons' crest, a yellow dragon, with a red tree on a black banner. This may be Gorlois' crest, considering that both Morgana and Morgause consider themselves as heirs to Gorlois' house, but it could also be the Blood Guard symbol, which represents the rowan tree on the Isle of the Blessed too.

Appearances
Series 1:

The Beginning of the End (first mentioned)

To Kill the King (mentioned only)

Series 2:

The Sins of the Father (mentioned only)

The Witch's Quickening (mentioned only)

Series 3:

The Tears of Uther Pendragon: Part One (mentioned only)

The Crystal Cave (mentioned only)

The Coming of Arthur: Part One (symbol only)

The Coming of Arthur: Part Two (symbol only)

Behind the Scenes
It is stated by fans that Gorlois's surname is "le Fay" but there is no source.