Agravain

Sir Agravain or Sir Agravaine is a nephew of King Arthur and a Knight of the Round Table in Arthurian legend. He is the second son of King Lot of Orkney and Lothian and Morgause , full brother to Gawain, Gaheris and Gareth. His half-brother and most frequent associate in the Post-Vulgate Cycle is Mordred. His mother's parents were Gorlois and Igraine; she was a sister of Elaine and Morgan le Fay and maternal half-sister to King Arthur. Agravain is described as handsome and a capable fighter, but unlike his heroic brothers Gawain and Gareth, Agravain has a reputation for malice and villainy. He plays an important role in most cyclical Arthurian literature, from the Vulgate Cycle to Malory's Le Morte d'Arthur when he exposes his aunt Guinevere's affair with Lancelot. Though Gawain, Gaheris and Gareth try to stop them, he and Mordred conspire to catch the adulterers together. In some versions he is killed by the escaping Lancelot, in others he dies defending Guinevere's execution from... full article at wikipedia