Who is sir Mordred and why does he meet the king Arthur's ship with an army?

Sir Mordred is a character from Arthurian legend, often depicted as the illegitimate son of King Arthur and his half-sister Morgause. He meets King Arthur's ship with an army as part of a power struggle for the throne, often portrayed as a traitor seeking to usurp Arthur's rule. This confrontation typically symbolizes the ultimate betrayal and conflict within the Arthurian narrative, leading to the downfall of Camelot. Mordred's actions are driven by ambition and a desire for revenge against Arthur for his perceived wrongs.