Charlemagne is a Saber-class Servant appearing in the Fate/Extella series. He is based on the legendary historical figure, King Charlemagne, who was known as the founder of the Holy Roman Empire. In the series, Charlemagne is depicted as a youthful, energetic, and charismatic swordsman, wielding the sword Joyeuse. He plays a crucial role as a protagonist, known for his leadership, strong sense of justice, and lighthearted personality, often forming bonds with other characters throughout the story.