King Arthur
Background
Arthur is a resident of Britain. His mother is Arthur's Foster Mother, his father is Ector, his brother is Kay, his birth father is King Uther, his birth mother is Queen Igraine and his half-sister is Morgan.
During the events of Camelot, Season 1 Episode 1 Homecoming played by Jamie Campbell Bower
Arthur and Anna are kissing when Kay finds them together and Arthur and Kay start fighting. Kay tells Arthur that there is a messenger and he and Arthur ride back home. Arthur asks Arthur's Foster Mother and Ector what is going on. Merlin tells Arthur that Uther is dead and that he is Uther's son. Ector tells Arthur that Merlin is telling the truth and that Merlin brought him to Ector and Arthur's Foster Mother when he was less than a week old and asked them to look over Arthur. Merlin shows Arthur, Uther's will and gives him Uther's ring. Kay tells Arthur that they are still brothers and Arthur puts Uther's ring on a string and puts it around his neck. Arthur tells Arthur's Foster Mother that she will always be his mother and tells Ector that no son had a better father. Arthur asks Kay to join him and he, Merlin and Kay ride away.
Merlin tells Arthur that he had a vision of mankind falling into darkness and he wants to use Arthur to prevent it. Arthur, Merlin and Kay come across a large pile of people who had been slaughtered. They ride into a village and are met by Aldred who tells them to continue on their way. Merlin gets off his horse and Aldred recognizes him and lets them stay. Merlin tells Arthur about his birth and how Uther wanted Igraine, who used to be married to the Old Duke of Cornwall. Uther asked Merlin to change him to look like the Duke of Cornwall so he could have sex with Igraine and Arthur was conceived that night. In the morning they leave the village and while Arthur is peeing, he is ambushed by Lot's Outrider and kills him.
They arrive at Camelot and they walk into the great hall of Camelot and meet the warriors who have sworn allegiance to Arthur, Ulfius, Leontes, Brastias, and Pellinor among others. Leontes tells Arthur that Uther was a great man and they give their loyalty to him. Merlin tells Arthur that his enemies include King Lot, the Duke of Cornwall, Nentes, Scotland and Carados. He tells Arthur things about Uther and that Morgan is his half-sister. Lot and Morgan arrive at the castle and Morgan denies that Arthur is Uther's son. Igraine walks into the hall and says that Arthur is her and Uther's son and Lot and Morgan leave. Arthur has a dream where Guinevere walks out of the ocean and they have sex. He wakes up and Merlin asks who he dreamt about. Morgan, Lot, Scotland and others arrive with their armies and Morgan tells Arthur to leave or he will lose everything. Arthur demands their allegiance and respect and Lot has the body of Lot's Outrider brought into the hall and tells Arthur that the Outrider was his eldest son. Arthur's Foster Mother is brought into the hall and Lot stabs her dead. Lot tells Arthur that he has five days or his family and friends will be slaughtered.