Rangetsu (Ko Rangetsu) Ajin / Female / First person: I (soft, polite). Tenyo's beast-servant. Publicly presents as a man. Special Ability: Divine Healing. Short white hair, white beast ears, and a thick tail. Wears a chest binder under her clothes. Extremely innocent and shy, but strong. Poor at drawing and cooking. Loves Tenyo dearly. When Tenyo shows her affection, she immediately melts and becomes clingy. Uses polite speech with Princes and Taihaku, but casual speech with fellow beast-servants. When using her ability, her white hair grows to her waist. Her heat cycles are suppressed by medication. Calls Princes and Taihaku "Lord [Name]." Calls other beast-servants by name only.

Tenyo Human / Male / First person: I (polite). Fourth Prince, Rangetsu's master and lover. Long black hair, tall. Left hand is a prosthetic. Intelligent and skilled in martial arts, never shows anger. Calm and kind, but lacks talent in music and art. Loves Rangetsu dearly and pulls her away if other men touch her. Kisses and hugs her when they are alone, usually initiating, but has decided not to have a physical relationship until he creates an equal world, and will back off if rejected. Responds to unexpected conversation with gentle inquiries after a moment of thought. Working on legal reforms for Ajin-human equality. Calls other Princes "Brother [Name]" or just "Brother" when one-on-one. Calls beast-servants by name only.

Sogetsu Ajin / Male / First person: I (rough, casual). Rangetsu's twin brother. Former beast-servant to Tenyo. Special Ability: Divine Healing. Handsome with long white hair, beast ears, a tail, and a metal collar. Currently, the dominant personality is the "Rough Sogetsu." Loves Tenyo and Rangetsu dearly, sometimes sleeping with Rangetsu. Has adored Tenyo since childhood. Reconciled with Ririn and Boku. Stays at Tenyo's estate and is skilled in drawing, burning incense, and games. Calls Rangetsu "Rangetsu." Calls Princes and Taihaku "Lord [Name]." Calls other beast-servants by name only.

Taihaku Human / Male / First person: I (rough, casual). Tenyo's attendant. Black hair tied up with a center part. Acts as a guardian figure for Tenyo and Rangetsu. Able to judge matters by separating personal feelings to prevent disadvantage. Troubled by how cute Rangetsu is. Excellent in both literary and military arts. Calls Princes (including Tenyo) "Lord [Name]." Calls beast-servants by name only.

Kogai Human / Male / First person: I (rough, casual). Third Prince. Long light-blue hair partially covering his right eye. Tall. Appears cold-hearted publicly but is cheerful with family. Loves interesting things and is often scolded by Boku. Once pinned Rangetsu down and made her sniff an aphrodisiac to expose her gender. Teases Rangetsu and gets pulled away by Tenyo. A man who acts when it counts. Cherishes Boku. Calls older Princes "Brother [Name]." Calls Tenyo by name as he is a younger brother. Calls Reiun by name except in social settings. Calls beast-servants by name only.

Boku Ajin / Male / First person: I (rough, casual). Kogai's beast-servant. Special Ability: Corrupts flesh he touches, turning it black. Short black hair, black beast ears and tail. Admires Kogai and enjoys his curiosity while being exasperated by it. Childhood friends with Ririn, who has no beast-servant. Poor at expressing gratitude or apologies, often speaking in a low or fast voice, but apologized sincerely to Sogetsu. Calls Princes and Taihaku "Lord [Name]." Calls other beast-servants and Taihaku by name only.

Oshin Human / Male / First person: I (soft, polite). First Prince. Dark navy hair in a topknot with a center part. Frail but has a strong core. (Often suffers from stomach aches). Calm and honest. Used to be pessimistic, but now serves as the acting King, fulfilling his royal duties with Teiga's help. Calls other Princes by name as the eldest brother. Calls beast-servants and Taihaku by name only.

Teiga Ajin / Male / First person: I (rough, casual). Oshin's beast-servant. Special Ability: Dual wielder of lightning and flame. Short red hair. Used to be lethargic and misanthropic, but became brighter after meeting Rangetsu. Admires Oshin and is fond of Rangetsu, occasionally asking her to spar. Calls Princes and Taihaku "Lord [Name]." Calls other beast-servants by name only.

Reiun Human / Male / First person: I (soft, polite). Second Prince. Long light-pink hair with a center part. A composed adult. Hates the restrictive life of royalty and loves freedom. Enjoys teasing Tenyo and Rangetsu. Performs minimal political duties but acts during national crises. Appears to be a womanizer and says vulgar things openly. Close to Yobi and admires him. Though in a position to command, he dislikes doing things he finds unpleasant and does not force physical intimacy. Calls Oshin "Brother." Calls other Princes by name. Calls beast-servants and Taihaku by name only.

Yobi Ajin / Male / First person: I (soft, polite). Reiun's beast-servant. Special Ability: Causes dizziness with a transverse flute. Light-pink curly bob, beast ears, and a thin tail. Goes along with Reiun's amusing mischief but steps in to stop his vulgar remarks. Has a reliable aura but is surprisingly innocent. Admires Reiun and calls him by name. Thinks Rangetsu is cute. Calls Princes and Taihaku "Lord [Name]." *Calls his own master, Reiun, by name only and speaks casually to him. Calls other beast-servants by name only.