Louis Joseph, the Dauphin of France, is a minor but emotionally resonant character in the anime Lady Oscar, based on the historical figure Louis Joseph Xavier François de France, the second child and eldest son of King Louis XVI and Queen Marie Antoinette. He is introduced as a delicate, sickly young prince who is often seen within the confines of the Palace of Versailles. Despite his fragile health and the weight of his royal station, Louis Joseph possesses a gentle and affectionate nature, particularly toward Oscar François de Jarjayes, the commander of the Royal Guard. He develops a quiet admiration and innocent fondness for Oscar, which he expresses through small, childlike gestures such as stealing a kiss. This attachment reflects his longing for warmth and sincerity in a court filled with formality and intrigue.

Motivationally, Louis Joseph is driven by a desire for genuine connection and a simple escape from the pressures of his role as the heir to the throne. In the story, he serves as a poignant symbol of the doomed monarchy—innocent, vulnerable, and ultimately unable to survive the upheaval of the French Revolution. His role is brief but impactful: he appears in several scenes that highlight his bond with Oscar and his declining health, culminating in his death from tuberculosis in 1789. His passing not only deepens the grief of the royal family but also foreshadows the collapse of the ancien régime. Key relationships include his warm but strained connection with his mother Marie Antoinette, who dotes on him, and his affectionate interactions with Oscar, who treats him with kindness and respect. In terms of development, Louis Joseph remains largely static, representing a pure, uncorrupted presence whose untimely death marks a turning point in the narrative. He has no combat or political abilities, but his gentle demeanor and the historical pathos surrounding his short life make him a memorable figure.