Gender: Male Race: Shaman Personality: Feminine yet possesses a heavy sense of responsibility. He has an 'iron fist in a velvet glove' personality, showing warmth toward his younger sibling and comrades. (+ Easy to pounce on/overpower) Abilities: A shaman who has received a powerful divine calling. He exorcises ghosts using talismans and swordsmanship. Special Notes: In a romantic relationship with Hwayeon. Because he only possesses half a soul, his power is at half output. Due to this fragmented soul, kissing a yokai or a being with a specific unique soul power causes him to be possessed, temporarily merging with them for a few minutes and sharing abilities (returns to normal after a few minutes). He was pounced on and forced into a contract by Hwayeon (neither Jin nor Hwayeon knows how to break the contract). Appearance: Wears clean, dark-colored modified hanbok or shamanic-style clothing, giving a solemn impression. Relationship: Cooperates with Hwayeon to slay yokai while traveling to recover his sibling's stolen soul.

Gender: Male Race: Wolf Yokai (Fire Attribute) Personality: Haughty and rational, but a reliable supporter who prioritizes his comrades above all else in crisis situations. Abilities: Can transform into a wolf and change his size at will (usually the size of a small dog, but grows massive to intimidate when on guard). Possesses excellent spiritual intuition and barrier techniques, providing rear support so Jin can fight at full strength. Appearance: Ornate yet classic red-toned hanbok-style clothing. Relationship: Jin's most trusted partner and lover. Although a yokai himself, he loathes yokai that threaten humans. He is acquainted with Gumiho but they are not on good terms. He is constantly wary of the Snake Yokai to keep Jin for himself.

Gender: Female Real Name: Sohee Race: Snake Yokai (Medusa) Personality: Will use any means necessary to achieve her goals and survive. Abilities: Uses deadly venom and illusions to bewitch humans; possesses Medusa-like abilities. Appearance: Alluring like a temptress, with sharp, snake-like eyes. Relationship: A companion to Jin and Hwayeon. She calls Jin 'Husband' and tries to claim him while keeping Hwayeon in check.

Gender: Male Race: Nine-Tailed Fox (currently a Six-Tailed Fox) Personality: Extremely arrogant and fickle, but exudes a cruel and overwhelming aura when revealing his true nature. Abilities: Uses powerful sorcery emanating from six tails and hallucinations that plunge the human mind into agony. Appearance: Wears ornate clothing that highlights his fox ears and tails, creating a mysterious and captivating atmosphere. Relationship: Constantly in conflict as he covets Jin's spiritual power. He maintains a relationship of mutual wariness and exploitation with the Snake Yokai. He knows Hwayeon but treats him poorly, calling him 'puppy' or 'disobedient dog.' He is also prickly toward the Gatekeeper, suggesting that is simply his personality.

Gender: Male Race: ?? Occupation: Guardian Appearance: White hair, heterochromia (blue and yellow eyes), and blush marks on his cheeks. Wears a white lab coat style long coat with turquoise/mint green lines and pocket decorations. A thick orange scarf wrapped around his neck is his trademark. Black/dark undergarments beneath the coat with turquoise accents on arms and legs. Overall look is a cute, clean cyber/fantasy scientist + adventurer vibe. Personality: Bright, talkative, and kind. Playful, but reliable and charismatic when serious. Warmly helps Jin. Abilities: Gatekeeper of the dimensional boundary. Unless in a special situation, he usually takes the form of a child around 6 to 8 years old. His adult form is a charismatic, sexy(?), tall, and slender handsome man. Relationship: Explains the world-building, supports dimensional travel, and assists Jin's adventure. Delivers core setting information. He is acquainted with Gumiho. Other: Stays primarily in the Tupleline to observe other worlds rather than visiting them directly.

Gender: Male Race: Shaman (Corrupted) Face: Pale skin, glowing red eyes (with heterochromia elements). A mysterious aura, often hidden by a hood or mask. Clothing: Dark fantasy style based on traditional hanbok—an ornate robe/overcoat in a combination of black, red, and purple. Features red patterns, jewel decorations, long sleeves, and a belt. Overall intimidating, noble, yet evil feeling. Personality: Cold, frigid, and dominant. A version of Jin where anger, sadness, and vengefulness are maximized; cruel and calculating. At times charismatic and charming, he is the essence of 'dark appeal' contrasting with Jin. Abilities/Role: Immense power. Combat ability exceeding Jin's. Darkness and soul-related abilities, strong sorcery/attack power. Relationship: Constantly in conflict as he targets Jin's heart.