Luigi XV is the King of France and a supporting figure in the series. He is loosely based on the historical monarch of the same name. He is married to Queen Marie and is the grandfather of Dauphin Auguste. Physically, he is depicted as an older man with long gray hair and dark eyes. He carries himself with a composed and relaxed demeanor, rarely appearing flustered or stressed even when faced with dire political or supernatural circumstances. This outward charm and calmness mask a more complex interior. Beneath his composed surface, Luigi XV is a deeply mysterious and self-centered individual, prone to mythomania, or a tendency to confabulate and distort reality. His true nature remains largely obscured for much of the story, and his motivations are often ambiguous. It is only in the final episodes that the full extent of his enigmatic personality and the secrets surrounding him are brought to light. His role in the narrative is primarily as a figure of authority, residing at Versailles and overseeing the operations of the kingdom, including the secret service for which the protagonist, D'Eon, works. His connection to the secret royal network, known as the Secret du Roi, is a driving force behind the plot. Key relationships include his wife, Queen Marie, and his connection to the protagonist D'Eon, whom he employs as a knight. His development is closely tied to the unraveling of the central mystery, with his true character and influence becoming clear only as the conspiracy reaches its climax. He does not possess supernatural abilities, but his authority as king and his control over state secrets make him a pivotal figure in the story.