Mordred.
King Arthur killed Mordred at the Battle of Camlann. Arthur was fatally wounded in the battle.
King Arthur die in the Battle of the Saxon's
After King Arthur returns to Britain and defeats and kills Modredus he is mortally wounded, and is taken to the isle of Avalon to be healed of his wounds, where he died.
King Arthur fought in twelve battles. There actually was one more battle, called the Final Battle. In it, King Arthur got fatally wounded and later died. Hope this helps!
The four men still alive at the end of the battle in King Arthur are King Arthur, Sir Bedivere, Sir Lucan, and Sir Bedivere's brother.
King Arthur's final battle was the Battle of Camlan. Historians have put this battle in various parts of the UK, but 'somewhere in Wales' is a popular guess. In this and other battles, King Arthur was fighting the Saxon invaders of his lands.
King Arthur's spear was called "Rhongomyniad." It was a powerful and legendary weapon that he used in battle.
King Arthur's evil step brother Mordred kills him blood thirsty for power over Camelot after being temporarily left in charge by king Arthur.
King Arthur was mortally wounded at the Last Battle. He had to be carried to the water's edge. His sword Excalibur was thrown to, and caught by, the hand of the Lady of the Lake. A barge then carried King Arthur to Avalon.
his son
The people of Cameliard were joyous when King Arthur and his men returned from battle, welcoming them with celebration and happiness.
If you're talking about the real life King Arthur, the only battle that people can decide conclusively that he fought in was the Battle of Badon Hill, where he defeated the Saxons. The battle at the end of the King Arthur film from 2004 is based on that battle. However, we really don't know that much about Arthur from history, as there isn't much archeology supporting his existence. Most scholars don't even think he was a king, but rather a war leader who brought peace to his area for close to half a century. If you were talking about the fantasy Arthur, then I can't really help you.