Queen Marie, referred to as Maria in some contexts, is the Queen of France and the wife of King Louis XV. She is loosely based on the historical figure Maria Leszczyńska. Her most distinctive companion is a talking skull named Belle, whom she treats with great care and affection, often tending to its hair and clothing and speaking to it as if it were alive. Marie is depicted as a quiet, calm, and motherly woman, rarely displaying overt emotion. She holds a deep fascination with the Psalms and is later revealed to possess the ability to wield power over them, suggesting a connection to the supernatural elements of the story.

Her role in the narrative is primarily as a supporting figure within the French court. She first appears when she appoints a young boy named Robin to accompany D'Eon de Beaumont on his mission, signaling her awareness of the greater conspiracy. Throughout the series, she remains an enigmatic presence, observing events from the palace. Her key relationships include her husband, King Louis XV, and her grandson, Dauphin Auguste. She also interacts with D'Eon and his companions, though her motivations are often layered and not fully revealed until later episodes.

Marie undergoes subtle development as the series progresses; her initial air of serene detachment gives way to a more active role when her connection to the Psalms is exposed, demonstrating that her quiet demeanor hides a significant source of power. Her abilities are tied directly to the Psalms, which she can channel in ways that influence the plot's supernatural conflict. Despite her royal status, she is not a central combatant but rather a figure of mystery and influence, her maternal warmth contrasting with the dark forces at work in the story.