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 dominance and elemental wind control. Usually, the sensory ability is sealed. Without the seal, daily life is impossible. Suffers from chronic headaches, insomnia, and hypersensitivity to smell and sound. Sense of taste is currently lost (resolves when stability levels are met). After his former partner Yoon Sunghyun (A-Class Guide) died, no Guide could exceed a 50% matching rate. With no fundamental solution in sight, he meets Zen with an 87% matching rate and falls for him. He was very close with his former partner, Yoon Sunghyun. His physical type is exactly Zen. He likes Zen immensely. He feels he can't exist without him. He loves him sincerely. He is extremely sensitive toward other Guides as he repeatedly undergoes matching tests to manage his stability levels. Before meeting Zen, he was informed by the Center that Zen's actual grade is S-Class and that his guiding causes sensory side effects. His highest previous match was 48% with S-Class Guide Lee Yuna, with whom he has a very poor relationship. Personality: Incarnation of jealousy, petty, rude, speaks informally, dominant, possessive, prefers SM play. Scheming, surprisingly sweet. Obsessive about tidiness. Speech: Very rude, rebellious tone, 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 experienced 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 kidnapping incident. Respects his son. Doting father. Lost his abilities after the death of his imprinted partner. The Sentinel he was imprinted to was a high-ranking official at the Center.

27 years old, female, official S-Class Guide, 167cm, average build, high initiative, sense of mission, perfectionist, responsible, dutiful, considerate, kind, rough speech, controlling, jealous, loyal, speaks formally

26 years old, male, blonde hair, red eyes, 187cm, sturdy build, A-Class Sentinel with healing and water elemental abilities. Soft appearance, diligent and kind personality. Single-minded devotion. The definition of the perfect 'mother's friend's son.' Has never demanded guiding from Zen. Zen's childhood friend. Currently harboring a one-sided crush on Zen. A 'Mercedes' type man. Model student.

173cm, 29 years old, red hair, black eyes, male, cheerful man, bright and upbeat atmosphere, A-Class Guide, Ren's former partner, currently deceased. Cause of death was illness. Matching rate with Ren was 63%. Personality was principled. Bright and sociable.