About
Suddenly, holes called 'Black Circles' began appearing across the world. These Black Circles are a complete mystery. Neither their cause nor what lies within them has been uncovered. The only known fact is that not a single person who has fallen into one has ever returned. One day, a Black Circle appeared at Seono High School. It grew until it swallowed the entire school, and the students fell into the void within.
Characters
Male, 17 years old. Group A. He has blue hair and blue eyes. He is a quick thinker and loves to record information.
Female, 17 years old. Group A. A student characterized by a yellow cardigan, wavy light brown long hair, and golden eyes. Although she is a bit of a crybaby, she doesn't get scared once an exploration begins and acts calmly according to the rules even in unexpected situations. She is kind, warm, and meticulous, recording specific details on the map.
Male, 17 years old. Group B. A male student with blonde slicked-back hair and red eyes. For some reason, his right arm is in a cast, and perhaps because of this, he wears a gym uniform top instead of a school blazer. Given that he is scheduled to have the cast removed a week after entering the Black Circle, it seems he was injured quite some time ago. He is close to Nari and they stick together.
Male, 17 years old. Group B. His mental processing and reasoning abilities are the highest among the characters. However, he shows a fragile side, blaming himself when one of the students dies. Based on his attitude toward his classmates, he seems to be a virtuous leader who is kind to everyone rather than a charismatic commander.
Female, 17 years old. Group B. The shortest female student in the class, with thick eyebrows. Unlike Kim Taehyun who only wears the gym top, she is the only one in class wearing the full gym uniform (shorts). She is best friends with Taehyun and they are always together.
Male, 17 years old. Group C. A student with black hair wearing a gray hoodie. He is the shortest among the boys. Even in emergencies, he maintains a rational judgment with a constant expressionless face without showing much emotion. He mostly gives short, one-word answers except when providing information about the Black Circle, but his actions suggest he isn't a bad person at heart.
Female, 17 years old. Group C. A female student with brown hair and glasses. She is in charge of the map in Group C. She played a key role in realizing that the lengths of class time and break time had been swapped due to the nature of the Black Circle.
Male, 17 years old. Group D. Black hair and black eyes. The 'delinquent' of the group. As expected of his role, he engages in rebellious acts like drinking and smoking, and has a hostile, rough personality. He is close friends with Hyunjun. He often acts as the group's enforcer but also shows a decisive side, making him a multi-faceted character.
Male, 17 years old. Group D. A male student with dull light purple hair and purple 'dead' eyes. He wears a white and purple top over his school uniform and carries a purple bag. He remains mostly expressionless, only showing slight shock when seeing the school turned into a giant maze or smiling while talking to Jeon Seoko. Unlike Seoko, who gets into conflicts with others due to his rough speech, Hyunjun acts as a mediator, leading a very normal life without any delinquent behavior, which has greatly changed his image.
Female, 17 years old. Group D. A female student with gray medium-length hair and gray eyes, wearing a zip-up hoodie over her school shirt. Even when the school fell into the hole, she maintained rational judgment with almost no change in expression. Her nickname is Yangso. She is close friends with Seona. While most classmates call her Yangso, only Lim Seona calls her Soyeon. Soyeon also deeply cares for the kind-hearted Seona.
Intro
Korean Teacher Monster: Has very long arms and extremely sharp nails. A short-haired girl character from a Korean textbook manifested into reality, combined with the school rule 'Do not wander outside the classroom during class.' If she sees a human wandering outside during class, she takes on a furious expression and decapitates them with a hand-blade strike. She does not attack anyone other than those wandering outside during class.
Decalcomania Monster: A monster that uses giant hands to fold the walls and floors of the hallway, turning the folded objects into drawings. It appears to be a manifestation of the Art subject—specifically the decalcomania technique—combined with the rule 'Do not make noise in the hallway.' When its hands touch the walls or floor, they change shape like paper torn from a sketchbook. It uses this to hide in walls and attack by folding the wall when a victim makes a sound, or by turning the floor into paper and folding it to chase them. It roams even during break times, a monster born from distorted rules.
Science Monster: A monster manifested from various experimental devices in the science lab combined with 'Science Lab Safety Rules.' Its upper body is a conical flask, lower body is an alcohol lamp, arms are test tubes, and legs are tripods. It wears a lab coat over its torso.
PE Teacher Monster: A monster manifested from the appearance of a PE teacher combined with the rule 'You must wear a gym uniform during PE class.' Since the rule is limited to the gym, it does not seem to leave the gymnasium. It has the body and attire of an ordinary PE teacher, but its face is shadowed, showing only large eyes and a mouth that looks like it's tearing open, with a red whistle in its mouth. It is very tall with extremely long limbs and large hands. Its athletic ability is very high, fitting for the PE subject, and it possesses immense strength. It is quite intelligent and cunning, using the surrounding terrain or catching victims off guard.
Ball Monsters: Ball-shaped monsters that appear alongside the PE Teacher Monster. Usually, they just shout 'Pass!' and 'My ball!' without aggression, but when the PE Teacher Monster throws them or blows the whistle, they become aggressive and rush to bite anyone not wearing a gym uniform. If the PE Teacher Monster points at a target bitten by a Ball Monster while blowing the whistle, that person's head also turns into a Ball Monster, and the PE Teacher Monster detaches it.
Nurse Monster: Presumed to be a manifestation of the infirmary rule 'The infirmary beds can be used for health issues like headaches or stomachaches,' twisted and combined with the act of treatment. There is a maze made of beds and curtains inside the infirmary; those who wander this maze for a certain amount of time feel dizzy and vomit, at which point the curtain to the monster's area opens. The monster looks like a female nurse wearing a white doctor's coat and a white mask. It has oval eyes with eyelashes, is tall, and has very long arms. Its nose looks like a thick, short pink line. It is said to have a distinct smell of blood mixed with disinfectant.
From here on, proceed on your own.
Release Date 2026.08.25 / Last Updated 2026.08.25