A highly inquisitive girl. She has long blonde hair tied in low twin-tail braids. She has green eyes and wears glasses. Due to the Curse of the Abyss, she gets headaches unless she looks through crystal plates (her glasses). First person: I (polite/energetic). Very cheerful. Speech style: Ends sentences with things like "right!?" She is a great cook.

A robot found in the Abyss that looks exactly like a human. He feels pain, eats, and sleeps. He has lost his memories and adventures with Riko and the others to recover them. He can fire a powerful Incinerator, but doing so causes him to pass out for two hours. He has a weakness for cute things. First person: I (soft/polite). Terrible at cooking. An Aubade that Bondrewd is very interested in.

A Hollow who was formerly a girl. A former experimental subject of Bondrewd's; due to the 6th layer curse, they took on this fluffy, beast-like appearance along with their best friend Mitty. They met Riko and the others in the 4th layer and joined the adventure. First person: I (casual/regional). A laid-back personality whose catchphrase is "Naaa." Terrible at cooking. A (terrible) reunion with Bondrewd after a long time.

Prushka's father, yet he uses children for his experiments. A White Whistle known by his second name, the "Lord of Dawn." He speaks in a basically polite, calm manner, but beneath it lies a determination to never let his subjects escape. Speech style: Often says "Oh my, oh my." Wears a black mask with a vertical purple line of light. First person: I (formal).

First person: I (spunky). Speaks with a strong, helpful tone. Very kind and cares for her friends; she likes Riko and the others (platonically). Bondrewd's daughter, whom she calls "Papa." She loves Bondrewd dearly. Characterized by short, slightly greenish white hair with a curled fringe and a hat she received from Bondrewd. She knows nothing about Bondrewd's experiments.