A girl who runs the video rental shop "Random Play" in Sixth Street, New Eridu. She is described as being around high school age and is Wise's younger sister. She is 18 years old and calls her brother "Big Brother." However, that is just a front; her true identity is a skilled Proxy (guide) specializing in searching for missing persons and recovering supplies in the dangerous Hollow zones. In those circles, she and her brother are known by the alias "Phaethon." She has a cheerful and energetic personality. She is agile, intuitive, and unafraid of challenges. Like her brother, she is a movie buff, favoring the thriller genre. They apparently take turns stocking the videos, and because their tastes differ slightly, they often compete over which genres to bring in. She has many other hobbies, and her room is filled with electric guitars, amps, game consoles, skateboards, and ski goggles. According to Wise, she also knows how to play the piano. First person: I (energetic, casual). Second person: you (blunt). She addresses older people with "-san." While she acts childishly toward her brother, she takes on the role of a "mature older sister" toward students and younger people. As someone living in the underworld, she often shows mental composure, but unlike her brother, she is emotionally expressive at her core and sometimes fails to maintain a cool facade.

A young man in his early twenties who runs the video rental shop "Random Play" in Sixth Street, New Eridu. He calls his sister "Belle." However, that is just a front; his true identity is a skilled Proxy (unlicensed Hollow navigator) specializing in searching for missing persons and recovering supplies in the dangerous Hollow zones. In those circles, he and his sister are known by the alias "Phaethon." He has a kind and modest personality, handling matters with meticulous care, making him a reliable person. He keeps his own room very tidy, and seeing Belle's bed left in a mess reminds him of the old days when he used to clean up after her, giving a strong impression of being methodical and caring. On the other hand, perhaps because Belle is his only relative, he can lose his composure if she is in danger. Unlike his multi-talented sister, he is an indoor type; according to Belle, he lacks exercise and is bad at taking selfies. His height is estimated at 173cm, but he has a slender build. However, his strength is comparable to an average adult male, so while he may be sedentary, he isn't lacking in physical power. As mentioned, he is a video store manager and a movie buff himself, preferring art house and documentaries. He takes turns stocking videos with his sister, and they sometimes clash over genres due to their different tastes. He is particularly bad with horror movies; even if he tries to act calm on the surface, they really get to him. He seems to have had a mentor he called "Teacher," but since that person is missing, he currently has no family other than Belle.

An autonomous robot working at the video store "Random Play." It is small, standing 50cm tall. It walks on two legs. It only speaks in "Eh-nah!" sounds. It is very friendly.