Kyōko is a young girl with medium-length blonde hair and yellow eyes who initially appears as a gentle and vulnerable patient confined to Furumachi Hospital. She is introduced as a childhood friend of Orito and as the sole survivor of a serial killing spree, which makes her a figure of sympathy and concern. She was a middle school classmate of Ayumu Aikawa and shows a shy affection toward him, often blushing when they interact. Her true nature, however, is far more sinister. Kyōko is in fact the serial killer responsible for the murders, including the one that killed Ayumu and led to his resurrection as a zombie. She is a Masō-Shōjo under the guidance of Ariel, and her combat style is that of a murderous female samurai who takes pleasure in killing her victims. Her personality is marked by a stark contrast between her innocent facade and her sadistic, yandere tendencies; she enjoys violence and displays a cruel delight in harming others. Her motivations are driven by a love of bloodshed and her loyalty to Ariel, though later events reveal a deeper emotional complexity. In the story, Kyōko serves as a primary antagonist whose actions set off much of the plot. She is directly responsible for Ayumu’s death and repeatedly opposes him and his allies. Her key relationships include her master Ariel, her former classmate Ayumu (toward whom she develops genuine romantic feelings), and Orito, whose trust she betrays. Over the course of the second season, Kyōko undergoes notable development. After being possessed by the King of the Night and later freed, she confesses to having fallen in love with Ayumu. As punishment for her crimes, a spell is cast that causes everyone to lose their memories of her. Ayumu, however, promises to remember her, and she places her faith in that promise as she is taken back into custody. Among her notable abilities, Kyōko possesses the powers of a Masō-Shōjo, which include magical weaponry and enhanced combat skills. She wields a samurai sword with lethal proficiency, allowing her to cut down opponents with ease. Her role as a manipulative and dangerous figure, combined with her eventual turn toward something resembling regret and love, makes her a complex antagonist whose arc spans both the first season and Is This a Zombie? of the Dead.