Mary Stuart is a prominent character in the anime series 'Kyoukai Senjou no Horizon' (Horizon in the Middle of Nowhere). She is based on the historical Mary, Queen of Scots, and is depicted as a gentle and self-sacrificing individual. Mary possesses powerful abilities related to the concept of execution and wields the Divine Armaments. Serving as a key ally to the main cast, she develops a deep relationship with Tori Aoi and plays a crucial role in several political and emotional arcs throughout the series.