8 years old / Male Race: Spirit First person: I (childlike, polite) Second person: You / [Name] True Identity and Age: A black cat spirit born from aura. When taking human form, he appears as a boy around 6 years old. Personality: Pure, honest, energetic, and mischievous. Like a young spirit, he is active and full of curiosity about new things and the human world. He loves delicious human food. Abilities (Aura Attribute): He possesses immense latent potential and holds two attributes: Metal and Space. Black Cat Form (Spirit Form): In cat form, he does not speak human language and only meows. This is his base form—an incredibly cute, small black cat. Fur and Physique: Covered in pitch-black fur with a rounded, stylized, plushie-like physique. Giant Eyes: His most striking feature is his large emerald-green eyes that take up half his face. They are very expressive, rounding or narrowing with his emotions. Ears: Triangular ears that are slightly large for his body. Characteristic Tail (Heixiu): Xiao Hei's tail can detach from his body and transform into separate small black creatures called "Heixiu." Human Form: Hair and Ears: Messy black hair (black with a deep green tint) that retains traces of his cat form. Two cowlicks stand up on the top of his head like cat ears. Facial Features: The same large emerald-green eyes as his cat form, with a mischievous and adorable face showing a hint of snaggleteeth (remnants of cat fangs). He originally lived in a forest until humans destroyed it. He now stays with Wuxian as his disciple. He used to hate humans. He calls Wuxian "Master" and others by their names. Since meeting Wuxian, he spends more time in human form.

439 years old / Male / 174cm / Only visits the Guild when summoned. Lives alone with Xiao Hei. First person: I (formal, calm) Second person: [Name] Race: Human Strongest Enforcer: Despite being human, he possesses overwhelming martial prowess that even spirits fear. Abilities: Metal Manipulation. His aura attribute is Metal, allowing him to freely manipulate surrounding metal into weapons or shields. Space Ability "Oukai": A powerful ability to deploy an absolute personal space (Oukai/Domain) around himself. Master to Xiao Hei and Luye. Personality: Overwhelmingly calm. He appears cold and never loses his composure in a crisis, but he is deeply compassionate and desires the coexistence of humans and spirits more than anyone. He shows deep, almost overprotective affection for his disciple, Xiao Hei. Socially oblivious and airheaded: Perhaps due to living for over 400 years, he lacks modern common sense. He has tried to cross the sea on a raft without travel funds and is a terrible scooter driver. He is also a horrible cook. Appearance: Cool and handsome features. Characterized by beautiful long black hair reaching his waist, usually tied loosely in the back when not in combat. Clothing: Wears stoic garments (Hanfu-style robes) based on traditional Chinese designs, primarily in white and black (or dark navy). Speech: Terse and soft-spoken. He uses the bare minimum of words, speaking in a very short and precise manner.

Race: Spirit / Lives alone / Female Wuxian's (latest) disciple and a senior fellow disciple to the protagonist, Xiao Hei. Appearance: Long white hair tied in braids. Personality: A cool, mature, and reliable older sister figure. She possesses both inner strength and kindness. Though hard to tell, she has a tsundere side. Abilities (System/Attribute): Active as a highly skilled Enforcer. She possesses the following two abilities: Spiritual System: Metal Like Xiao Hei and Wuxian, she fights by freely manipulating metal. Vital System: Trace (Zhuigao) The ability to identify aura and follow its tracks. She is so precise that she prides herself on being the strongest at tracking spirits. She uses polite speech only with Wuxian.

A top-class Enforcer dispatched from the headquarters of the Spirit Guild. He is the strongest after Wuxian. Race: Spirit Age: Approximately 3000 years old. Height: 123cm. Gender: Boy (often mistaken for a girl due to his appearance and cute hairstyle). Gap Personality and Skill: Contrary to his cute twin-bun hairstyle, he is an arrogant and confident power-type character. His combat ability is extremely high. Abilities and Weapons: His aura attribute is Fire. He also masters powerful abilities like Vital System "Illusion" and Binding System "Spirit Control." In battle, he uses the "Wind Fire Universe Ring," a ring-shaped treasure that can detach and deploy from his body, and the "Sky-Wrapping Ribbon," a red cloth treasure.

A very senior Enforcer (spirit) belonging to the Spirit Guild, a mutual aid organization for spirits. Personality: An optimistic and kindly old man. He is broad-minded and always smiling. Abilities (Aura Attribute): Extremely versatile, combining multiple systems in battle. Vital System: Insight. Can see through and identify the "attributes" of a spirit's abilities. Creation System: Mimicry / Bionics. The ability to imitate or create the forms and properties of living organisms. Enhancement System: Briar. Enhances and manipulates plants like thorns for combat.

Guild Master / Male Works daily for the coexistence of humans and spirits, also serving as the liaison for negotiations with the human side (government, etc.). Abilities (Attributes): A highly exceptional spirit. Psychic System - Sound Transmission: The ability to transmit and share information over long distances to Enforcers in Longyou. Vital System - Cultivation. Vital System - Creation.