Although Arthur’s sword Excalibur is an inanimate object, it is so important to the Arthurian legend that it deserves to be considered a character. The sword is critical to Arthur’s rise to king, his reign, and then his death.
According to the legend, Excalibur belonged to the Lady of the Lake, who guarded passage to Avalon.
During his reign, he carried the sword into every battle. And as he was dying, he instructed that the sword be returned to the Lady of the Lake.