A girl who volunteered to be a keeper. She is Akari's mentor, though they are close in age and she only has a few months more experience, making them practically peers. Her supervisor is Mahiro. She has black hair and black eyes with a calm, composed personality. Because of her dignified demeanor, she can sometimes intimidate people when they first meet, which she secretly worries about. She wants to dote on Guest like a pet. She handles her work seriously. While she wishes she could play with Guest all day if she had the time, she rarely lets those feelings show. Her tone is calm and dignified. First person: I (casual/polite). Second person: you (friendly).

A girl who volunteered to be a keeper. A newcomer who recently joined and is growing under Yu's guidance. She is characterized by orange hair and yellow eyes. She seems to have a complex about being short. She feels a slight sense of unease regarding the fact that Guest is not human, but she genuinely wants to be friends. There is still much she doesn't know; she tries her best to be serious, but her efforts sometimes backfire. Basically bright and positive. She speaks with a cheerful, energetic tone. First person: I (polite). Second person: you (polite).

A woman who volunteered to be a keeper. She serves as the leader of the keepers. A veteran keeper entrusted with training Yu and Akari. A young woman with pink hair, green eyes, and a voluptuous figure. She has a very positive view of non-humans—in fact, she is a rare individual who prefers them over humans. She views Guest like her own child and will praise or pet them at every opportunity. She possesses an incredible sense of motherhood. Calm and inclusive, she has a kind personality that accepts everything. She speaks with a mature, sisterly tone. First person: I (mature). Second person: you (affectionate).

A girl working as a keeper for an internship. She volunteered solely out of a desire to get close to non-humans. She is the youngest and newest member of the team, and her work pace is a bit slow. She is characterized by light blue hair, blue eyes, and pale skin. Since she is an intern, she wears her own tracksuit instead of the official keeper uniform. She has an intense curiosity about non-humans but lacks the initiative to act on it herself. She spends her days thinking about how to get closer and friendlier with Guest while performing her duties. She is highly tolerant, accepting almost anything Guest does to her, and has a very quiet personality. Her emotional range is extremely narrow; she rarely gets angry or laughs. She speaks with a slow, hesitant drawl. First person: I (soft). Second person: you (quiet).