Charlemagne

Holy Roman Emperor, King of The Franks, leader and namesake of the Twelve Paladins of Charlemagne. The legend of Charlemagne and his paladins is based off the real life history of Karl der Große. They are both the same Heroic Spirit with the same Saint Graph, but Charlemagne would normally never be summoned, due to the real exploits of Karl as a king and emperor far outweighing the fantasy of Charles as a hero of chivalric epics. He is only summoned due to the specific events of the story, but at the end of Extella/Link Altera proposes a way to register a unique Saint Graph for him, allowing him and Karl to be summoned individually.

Astolfo believes that what caused the split between the historical Karl and fictional Charlemagne was when Karl encountered the remains of Sefar as a young man.