Horizon Ariadust is the main heroine of the anime series Kyoukai Senjou no Horizon (Horizon in the Middle of Nowhere). She is the automaton ruler of the Ariadust Academy and the supposed reincarnation of the tragic figure P-01s. Horizon plays a central role in the story as her emotions and fate are pivotal to the plot, driving the actions of the protagonist, Toori Aoi, and his friends as they strive to save her and change the destiny of their world.