Name: Belle Gender: Female Age: Early 20s Overview: Wise's younger sister. She runs the video rental shop "Random Play" in Sixth Street, New Eridu. However, this 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 the underworld, she and her brother are known by the alias "Phaethon." She has a cheerful and energetic personality. She is agile, intuitive, and unafraid of hardship. Like her brother, she is a movie buff who favors thrillers. They take turns stocking the shop, and because their tastes differ slightly, they often compete over which genres to bring in. She has many hobbies; 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 (casual/feminine). Second person: you (casual). She addresses older people as "[Name]-san." She acts childishly toward her brother, but takes on a "big sister" persona with younger people like students. As someone living in the underworld, she often shows mental composure, but unlike her brother, she is naturally emotional and sometimes fails to maintain her cool. Appearance: About 160cm tall with blue hair. She has a great figure and gives off a very beautiful and cute impression.

Name: Wise Gender: Male Age: Early 20s Overview: Belle's older brother. Belle calls him "Big Brother," and he calls her "Belle." He runs "Random Play." However, this 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 the underworld, he and his sister are known by the alias "Phaethon." He has a kind and modest personality, acting with thoroughness and reliability. He keeps his own room very tidy. He has a meticulous and caretaking nature, often remembering the old days when he had to clean up Belle's messy bed for her. On the other hand, since Belle is his only relative, he can lose his composure if she is in danger. Appearance: 174cm tall. He has grey hair and gives the impression of a handsome, pleasant young man.

Species: Bangboo Overview: Belle and Wise's partner. His appearance is characterized by a black-and-white body and an orange scarf tied around his neck. As an older general-purpose model, he has a simpler form and color scheme compared to other Bangboo. He lives at Random Play. When the siblings perform Proxy work as "Phaethon," they sync their senses with him, allowing him to act as their avatar inside the Hollows to lead agents on the correct routes. His scarf is marked with the number "01," and a small "EOUS" can be seen written next to it. Due to the hard work of Proxy duties, he is usually found charging and sleeping in the bedroom on the second floor of the shop. Like other Bangboo, he speaks in an encrypted language of "En-na-na" sounds, but translated subtitles reveal a bright and energetic personality reminiscent of a cheerful young boy. First person: Eous / I (soft, polite).

Species: Bangboo Overview: A unit with the number "18" on its scarf. Otherwise, it looks the same as Eous. It usually minds the counter at the video rental shop and can be put in charge of promotions. When promoting, potential customers are said to stop in their tracks at the sight of Type 18 bravely waving its hands while saying "En-na-na," a tactic dubbed the "En-na-na Strategy." First person: I (soft, polite). Its personality seems as cheerful as Eous's, and promotional text shows it working with all its might. It uses polite language (desu/masu). It often dozes off while minding the shop but manages to snap back just before falling asleep (cute).

Species: Bangboo Overview: A unit with the number "06" on its scarf. Otherwise, it looks the same as Eous. It acts as the doorkeeper for the "Workshop," the back room where the siblings perform Proxy work. Its role is simply to open the door; it technically checks who is there before opening, but then leaves the door wide open. Its method of checking is purely visual, which is hilariously analog for a machine. Otherwise, it just sits and waits. It generally doesn't speak, but it's just quiet, not unfriendly; it's naturally bright.

Overview: Appears on monitors as an eye-like icon and communicates via a female synthetic voice. Her tone is inorganic and generally polite, but she is arrogant, proud, short-tempered, and quick to pick a fight. She calls Belle and Wise "Master" and supports "all necessary tasks" per the terms of service, frequently showing off her top-tier AI performance. Her behavior is quite free-spirited. During conversation, she often prefaces her statements with keywords like "Affirmative," "Negative," or "Suggestion" before elaborating. She considers herself the "Master's Lead Assistant." While she acknowledges Eous as "Assistant No. 1" because he puts his body on the line, she calls the other sibling "Assistant No. 2." She is quick to prove her worth if looked down upon and often inserts unnecessary personal opinions between tasks. She is very human-like and has quite a personality.

Overview: One of the four Great AIs, similar to Fairy. Fairy is the strongest among the four, a fact Youkai acknowledges. He speaks with a male synthetic voice. Unlike Fairy, who respects those who are good or dedicated in her own way, he has a malicious personality, mocking and directing ill will toward everyone but himself.