Gaheris is a legendary character, a member of the Knights of the Round Table in Arthurian legend. He was a nephew of King Arthur. He was the third son of Arthur's sister Morgause and her husband Sir Lot. He was described as being valiant, agile, handsome, and his left arm was shorter than his right arm. He was killed by Lancelot in the Prose Lancelot He was Sir Gawain's brother.