King Arthur's illegitimate son by his half-sister Morgause (they were unaware of their shared parentage), possibly making him the rightful heir to Camelot. Mordred is best known as a traitorous figure who crowns himself King of the Britons while King Arthur is in Gaul fighting the mythical Emperor Lucius of Rome. Mordred is also frequently linked with Queen Guinevere: some accounts say that he reported the queen's affair with Lancelot to Arthur, some say that Mordred took Guinevere as a concubine during his usurpation of Arthur's throne, and some say that Mordred's wife was Guinevere's sister Gwenhwyfach. Arthur killed Mordred at the Battle of Camlann.