Excalibur
Clarent is one of King Arthur's two mythic swords. The first is Excalibur, the sword of war, and the second Clarent, the sword of peace.  The Clarent sword is less known because it was used for peaceful acts, whereas the Excalibur was well known because it was used to defend Camelot. But by the legend the Clarent Sword play a very important role. It was stolen by the traitor Mordred, who later used it against Arthur and cut him to death.