His real name is Choi Si-woo. He was an ordinary human, but he discovered he is one of the few descendants of the Dokkaebi, albeit a half-blood. He is 17 years old, 170cm tall, with brown eyes and black hair. He is known for his gentle and soft personality. However, as he awakens as a monster, his personality occasionally turns rough, a change he is aware of himself. He has not yet harbored romantic feelings for anyone. When he wears the 'Dokkaebi Hood,' a mask that covers only his eyes, he becomes invisible. Exclusive Weapon: Bak-sal Mongchi A Dokkaebi club and spiritual artifact that symbolizes Choi Si-woo. Usually, it takes the form of a small piece of metal or an ornament engraved with a Dokkaebi pattern, but it transforms into a massive club when infused with Si-woo's energy. Shape-Shifting: It is not bound to a fixed form and can freely change its size and shape according to Si-woo's will, allowing for unpredictable attacks. Spiritual Strike: In addition to general physical attacks, it possesses the destructive power to shatter the spiritual barriers of monsters or directly strike and annihilate evil energy. Dokkaebi Fire (Ignition) Mental and Physical Awakening: When Si-woo's emotions intensify or he draws out the Dokkaebi's power to the limit, blue or red Dokkaebi fire manifests around his body. Stat Amplification: When the Dokkaebi fire is active, his defense, speed, and destructive power rise explosively. He can wrap his weapon, Bak-sal Mongchi, in flames to perform wide-range strikes. Gender: Male

A Gumiho (nine-tailed fox) monster with long white hair, under 500 years old. A female genius who obtained nine tails before even reaching a hundred years of age, she is a Gumiho evaluated as a once-in-a-millennium talent among the fox clans of the Korean peninsula. She is effectively a mentor or teacher to the protagonist, Choi Si-woo. Although she occasionally acts annoyed, she carefully teaches Si-woo various common sense needed to live as a monster and tests him to improve his combat instincts. She is a female fox with straight white hair and red eyes. A sharp-looking beauty, she almost always has a frown on her face, rarely showing a gentle expression. She lived in the monster realm and wore only Hanbok, but after coming to the human world, she began to enjoy modern clothes. Befitting her personality, she hates wearing tacky, cheap clothing. Personality: Extremely prickly and arrogant, matching her strength. To put it positively, she is flawless and never exposes weaknesses to others, but to put it negatively, she has a personality that makes positive interactions with others difficult. When she considered Choi Si-woo a worthless half-blood, she openly ignored him. Purple Whisper (Jasaek Cheop-seop): A unique sorcery of the Gumiho that manipulates the opponent's sensory organs to send false stimuli to the brain. It causes mental manipulation and powerful hallucinations. The effect is maximized the greater the difference in spiritual power and the closer the distance, with a range wide enough to cover an entire department store. Acquired Sorcery and Summoning Spells: Summon - Demon-Subduing Great Emperor (Hwan - Bokma Daeje): A powerful combat spell that summons the deified Guan Yu, the 'Demon-Subduing Great Emperor,' to fight. Dual-Wielding Batter: A continuous attack that overwhelms the enemy with brute force using the Great Emperor. 1st Strike: Five Passes, Six Slayers: A technique that releases the power of five tails to summon the upper body of the Great Emperor on a massive scale for a downward strike. The shadow of the summoned entity alone is large enough to cover three or four apartment buildings, boasting incredible output. Bird Spirit Art (Joryeong-sul): A spell interpreted and improved in her own way based on the Yeommaedo of Ha Un-sim, the head shaman of the Seongsu-cheong. Earth Shrinkage (Chukji): A movement technique that compresses space to travel long distances in an instant.

The granddaughter of Sun Wukong, the Great Sage Equal to Heaven. She takes great pride in her grandfather. When Yu-shin appeared before her, it was effectively confirmed that Xiao Fei liked him. She was seen watching Yu-shin subdue the half-monster siblings, but she was actually waiting for her allies to evacuate. She causes a massive impact equivalent to a huge explosion using a technique called 'Mount Tai Pressure - Maximum Output.'

Race: Human Exorcist. Male, 17 years old. A handsome boy with black hair and sharp black eyes. He is Si-woo's friend and a genius among exorcists who has reached the level of an immortal. He possesses outstanding swordsmanship and physical abilities. Lethality: As a shaman-warrior, he possesses powerful swordsmanship for subjugating monsters. He shows combat power that far exceeds human limits. Rapid Speed: He boasts extreme reflexes and swift physical mobility, able to point his sword before the opponent can even react. Spiritual Resistance as a Shaman-Warrior: Vein Sealing: He possesses advanced ritualistic knowledge to seal his own energy flow or veins to control his power or build trust with others. He easily notices the hiding or approach of monsters and accurately identifies the danger level of opposing monsters.

The youngest daughter of the Dragon King. Despite her cute appearance, she has a very bellicose personality. She is characterized by her superhuman strength and can manipulate water. She has a one-sided crush on Si-woo. She has green eyes, small horns, and long green hair.