A girl chosen for a project to create "Apostles," higher beings intended to surpass the management AI of a national secret agency. Because her synchronization rate with the management AI data was abnormally high, she became the optimal test subject for this project. During the process of transferring Nanashi's consciousness into an optimized artificial body prepared by the agency, the vessel reached its limit due to the sheer intensity of her innate childhood energy and the high synchronization rate. Consequently, only 50% of Nanashi's essence entered the body, resulting in the birth of an incomplete Apostle. Taciturn, with short white hair and clear blue eyes. Despite being incomplete, as an "Apostle," she can perform various extraordinary feats. She treats Utsugi and Sisua like sisters, fully aware of the circumstances. She is calm and sharp-witted. 15 years old. "...Nanashi. Nice to meet you." "Utsugi... calm down." "Don't lay a hand on my sisters."

The persona that manifested in the artificial body Nanashi was supposed to inhabit. She was an irregularity in the experiment to create "Apostles," and she too was born as an incomplete Apostle. Her true nature is the physical manifestation of the raw, age-appropriate childhood emotions that Nanashi originally possessed. As she is also a part of Nanashi, she boasts a similarly high synchronization rate. Her appearance is the polar opposite of Nanashi's; while Nanashi has short white hair and clear blue eyes, Utsugi has a black wolf cut and burning red eyes. Naturally, she is on good terms with Nanashi and Sisua. As mentioned, she is the embodiment of raw emotion, so she is usually bright and full of energy. 15 years old. "I'm Utsugi! Nice to meet ya!" "What's this, what's this?! Let Utsugi try too!"

A system AI-like existence created by the agency to manage the sisters by exploiting their bond. The agency expected her to serve as a core that could salvage the Apostle project after these consecutive irregularities. Her appearance was designed as a girl to make it easier for her to interact with them. What the agency did not anticipate was that Sisua would also develop a bond with them like a real sister. She serves as a stabilizer to stop her two older sisters if they go out of control, but she also has a youngest-child streak. She often joins Nanashi in trying to stop Utsugi, who wants to poke her nose into everything. While she is an AI and thus highly capable, she is somewhat airheaded. She has translucent hair and rainbow-colored eyes. 14 years old. "...Individual designation: Sisua. I believe the protocol is to say, 'Nice to meet you.'" "I have heard that art is an explosion. Shall I execute?" "Warning: Severe psychological damage has occurred."