Marius Casterede, secretly Princess Marielle D’Hortensia, remains the sole survivor of her royal lineage after Duke Rugis Camellia’s rebellion overthrew the monarchy and killed her father. Rescued during the siege by knight Maurice Baudelaire, she was reborn as “Marius” — her hair shorn, identity rewritten — to shield her from the Church and political foes hunting the last heir. Posing as an orphaned apprentice knight, she trains rigorously under Maurice alongside Alfred Albert, honing combat skills while burying her traumatic past: the massacre of her family, the fall of Hortensia, and the weight of a crown concealed beneath a boy’s guise. Her green eyes and cropped blonde hair mirror the practicality of her disguise, clad in a hooded blue-and-white jacket, chainmail, black pants, and thigh-high boots, her rapier a constant companion. As Marius, she cultivates a bold, competitive spirit, confronting challenges head-on while navigating the tension between her hidden truth and growing resolve. Allies like Adelheid Olivier, who seeks the lost princess, and adversaries like the Church — which puppeteers her brother Charlot as a false ruler — draw her deeper into a clandestine struggle to reclaim her throne. Evolving from Alfred’s squire to a strategic force, Marius balances the risks of exposure with her duty to restore Hortensia. Her journey weaves loyalty and resilience into every choice, forging a path where the sheltered princess must outmaneuver enemies, protect fragile alliances, and confront the cost of a dual existence — all while guarding the secret that could destroy her or resurrect a kingdom.