Maria Antoinetta in the anime Lady Oscar is a fictionalized portrayal of the historical French queen, sent from Austria to France as a young teenager to seal a political alliance through her marriage to the Dauphin, the future Louis XVI. She arrives at Versailles full of youthful energy and a desire for affection, but quickly finds herself constrained by the suffocating etiquette of the French court and the emotional distance of her husband. This isolation shapes much of her early personality, which is marked by a frivolous and carefree exterior; she seeks distraction in lavish parties, extravagant clothing, and expensive jewelry, behavior that later fuels public resentment against her.

Her motivations are driven by a longing for personal happiness and genuine connection. She quickly forms a strong bond with Oscar François de Jarjayes, the captain of the Royal Guard, after Oscar saves her from a kidnapping attempt. From that moment, Maria Antoinetta regards Oscar as her dearest friend and protector, often turning to her for support and guidance amidst the intrigues of Versailles. Her most intense emotional relationship, however, is with the Swedish count Hans Axel von Fersen, with whom she begins a passionate but forbidden romance. This affair, together with her close friendship with the manipulative Duchess de Polignac, deepens the scandals surrounding her and contributes to her growing isolation from the court and the public.

Within the story, Maria Antoinetta serves as a central figure whose personal journey mirrors the decline of the ancien régime. She initially embodies the insouciance of royalty, but as the narrative progresses, she faces mounting political and personal crises. The death of her young son, the mounting debt from her spending, and the Affair of the Diamond Necklace all erode her position. She develops from a naïve girl into a more stubborn and determined queen, though she remains politically naive and unwilling to embrace reform. Her role becomes increasingly tragic as the revolution unfolds, and she is ultimately captured and executed.

Her most notable traits are her strong will and her capacity for deep loyalty. Though often described as childish or spoiled early on, she demonstrates resilience during her imprisonment and maintains her dignity until the end. She does not possess any combat or unusual abilities, but her influence on the court and her symbolic role as queen make her a key driver of the political turmoil. Her relationships, especially with Oscar and Fersen, are the emotional core of her arc, highlighting themes of friendship, love, and the cost of royal privilege.