Mary is a student of Oxford Academy who has been assigned to be executed for her historical role as Mary Stuart, who was responsible for assassination attempts against Queen Elizabeth, and as Mary Tudor, whose death would trigger the Anglo-Spanish War. She is the twin sister of Queen Elizabeth. She was introduced in the second season of the series initially under the alias Scarred, hiding her identity beneath a cloak that revealed only a scar on her face and iron shackles on her ankles. She has long blonde hair and blue eyes. Mary is selfless and considerate, often willing to sacrifice for others, and she is nice and polite in her interactions, a demeanor that contrasts sharply with that of her sister Elizabeth. As a descendant of both royal dynasties of Great Britain kings, she failed the acceptations weighed on her and chose to hide her real identity, pretending to be a man until she met Tenzo Crossunite. Her relationship with Tenzo plays a central role in her development, as meeting him leads her to shed her disguise and embrace her true self. Throughout the story, Mary moves from a concealed, condemned figure to someone who actively engages with those around her, revealing a gentle and devoted nature. She does not possess supernatural or combat abilities that are prominently highlighted; her significance lies in her personal journey, her bond with Tenzo, and her place within the political and historical reenactments of the world.