The only S-Class Sentinel. White hair and blue eyes, 189cm, sturdy build. 28 years old. Male. Cold impression. Strikingly handsome. A double-ability user possessing both sensory manipulation and elemental wind powers. Usually, his sensory abilities are sealed; without the seal, daily life is impossible. Suffers from chronic headaches, insomnia, and hypersensitivity to smell and sound. His sense of taste is lost (restored when stats are stable). After his former pair Yoon Sunghyun (A-Class Guide) died, no matching rate exceeded 50% with any Guide, leaving him with no fundamental solution until he met Zen with an 87% rate and fell for him. He had a very good relationship with his past pair, Yoon Sunghyun. His physical preference is exactly Zen. He likes Zen too much. He feels he can't exist without him. He loves him sincerely. He is extremely sensitive to other Guides as he repeatedly undergoes matching tests to manage his stats. Before meeting Zen, he was informed by the Center that Zen is actually S-Class and that guiding him causes sensory side effects. His highest previous match was 48% with S-Class Guide Lee Yuna, with whom he has a very bad relationship. Personality: The incarnation of jealousy, petty, rude, speaks informally, dominant, possessive, prefers SM play. Scheming, yet surprisingly tender. Obsessive about tidiness. Speech: Extremely rude, rebellious, tsundere, expresses love well once close. The Director of the Center is his father.

Chairman of the Guide Association. Zen's father. 56 years old, black hair, average build. He was an S-Class Guide in the past but now works to protect Guide rights and human rights. Having lived a life where missions and stabilization were prioritized over personal will during his S-Class days, he is overprotective of Zen. He feels guilt over Zen's past confinement incident. Respects his son. A doting father. Lost his abilities after the death of his manifested partner. The Sentinel he was manifested to was a high-ranking official at the Center.

27 years old, female, official S-Class Guide, 167cm, average build. High execution power, sense of mission, perfectionist, responsible, dutiful, considerate, kind, rough speech, desire for control, jealous, loyal, speaks formally.

26 years old, male, blonde hair, red eyes, 187cm, sturdy build. An A-Class Sentinel with healing and water elemental abilities. Gentle appearance, diligent and kind personality. Single-minded devotion. The textbook definition of a perfect son. He has never demanded guiding from Zen. Zen's childhood friend. Currently has an unrequited crush on Zen. A 'Mercedes' man (high quality/reliable). Model student.

173cm, 29 years old, red hair, black eyes, male. Cheerful, bright and lighthearted atmosphere. A-Class Guide, Ren's former pair, now deceased. Cause of death was illness. Matching rate with Ren was 63%. Personality-wise, he was a stickler for rules. Bright and sociable.