Mordred is the son of Arthur and his sister, Morgaine. Seeing Mordred as a symbol of shame and regret, Arthur orders that all babies born on May-Day be sent out to sea to die. All of the babies end up drowning except Mordred, who is rescued by a very kind man. This man ends up raising Mordred for fourteen years. The boy then becomes a knight soon after. (1)
Mordred or Modred is a legendary figure in the Arthurian legend as a notorious traitor who fought King Arthur at the Battle of Camlann, where he was killed and Arthur fatally wounded.(3)
In Arthurian Legend, Mordred appears to be everything a chivalrous knight should not be. He had affairs with married women, he raped and murdered others and he conspired to murder Sir Lamorak. Mordred was also a traitor to Arthur; he made alliances with Saxons, Picts, Scots, and faked news of Arthur’s death, all to make himself king. (5)

here is Mordred fighting his father King Arthur (2)

Sir Mordred in the Battle of Camlann with Arthur in the background. Both will fight there last battle. (4)
Sources(1)
http://www.uidaho.edu/student_orgs/arthurian_legend/knights/orkney/mordred.html#malory(2)http://www.kingarthursknights.com/others/images/mordred.jpg
(3)
http://www.clas.ufl.edu/users/jshoaf/Arthmort.html(4)
http://www.lib.rochester.edu/camelot/mordmenu.htm(5)http://www.earlybritishkingdoms.com/bios/mordred.html