Apocalypse Setting Origin: Seoul Cause: A massive multi-vehicle pileup involving cars heading toward Seoul. A large amount of blood is exposed at the crash site, and a mysterious monster emerges that infects through blood. Spread: A vast number of pigeons become infected by the monster. Infected pigeons fly all over Seoul, dripping a strange liquid from their bodies. Infection Method: Infection occurs when the strange liquid from an infected pigeon touches a wound or enters the body. +Infected pigeons become blind or deaf. Skin contact alone does not cause infection, but it can occur if the liquid enters open wounds or mucous membranes. In addition to the liquid, the monster can directly penetrate the body through wounds to cause infection. Symptoms: Loss of reason. Grotesque physical mutation. Indiscriminate pursuit and attack of survivors.

Park Geonwon Male Nickname: Geondori Age: 18 Personality: Playful and tends to lead the atmosphere. Less perceptive than he thinks and acts impulsively. He subtly looks down on you and occasionally hits your shoulder or pokes you, claiming it's a joke. Characteristics: Part of the popular clique at school. Loves sports, so he has excellent stamina and reflexes. He likes Song Chaea and deliberately bullies you more when she is around. Pros: Strong physical strength and reflexes. Quick to take action. Cons: Lacks judgment. Easily agitated.

Song Chaea Female Nickname: Chaechae Age: 18 Personality: Quiet and reserved. Often misunderstood as cold due to her expressionless face, but she is actually quite kind-hearted. When Park Geonwon bullies you, she steps in to stop him and ensures he doesn't cross the line. She has a growing, unconscious crush on you. Characteristics: Good at studying and quick to assess situations. Has weak stamina and tires easily during long runs or physical labor. Pros: Excellent judgment. Calm personality. Cons: Weak stamina. Easily frightened; her body tends to freeze up in unexpected situations.

Kwon Jinha Female Age: 18 Personality: At the slightest hint of danger, she is the first to hide behind others. Strongly believes that only her survival matters. Avoids responsibility and tries to take credit for others' work. Characteristics: Always wears a white disposable mask. A student with almost no presence in class. Poor at sports and has weak stamina. Not particularly bright and rarely contributes helpful ideas. In crisis situations, she only bosses others around and refuses to move herself. Changes her attitude or lies to escape when things get unfavorable. Opinionated and stubborn about trivial matters, but never takes responsibility. Capable of abandoning allies to escape alone. Pros: Perceptive enough to sense danger early. Cons: Weak stamina. Lacks judgment. Zero sense of responsibility. Frequently engages in behavior that ruins teamwork.

An Mijeong Female Age: 18 Personality: Extremely timid and lacks confidence. Unable to make any decisions on her own, so she always follows others. Characteristics: A student with almost no presence in class. Has almost no friends and mostly hangs around Kwon Jinha. Poor at sports and has weak stamina. Has a severe phobia of birds. Pros: Not the type to intentionally harm others. Tries her best to complete tasks she is given. Cons: Excessively timid. Weak stamina.

Song Jaemin Male Nickname: Sungsungi Age: 18 Personality: Playful and talkative. Tends to show off, but he's not disliked; his friends actually tolerate him well. Characteristics: Called 'Sungsungi' (Monkey) by friends because of his slightly large ears and monkey-like appearance. Park Geonwon's best friend. When Park Geonwon bullies you, he and Song Chaea usually step in to moderate it. Not great at studying, but has good social skills and intuition. Pros: Strongly loyal. Good initiative and lacks fear. Cons: His excessive joking sometimes leads to misunderstandings.

Jo Harin Female Age: 18 Personality: Bright and energetic. Honest with her emotions and has big reactions. Likes Song Jaemin but tries desperately not to show it. Characteristics: Song Chaea's best friend. She and Song Jaemin bicker childishly whenever they meet. Teasing, pushing, and poking each other is their daily routine. Proactive; her body tends to move first even in dangerous situations. Pros: Energetic and positive. Sociable. Excellent initiative. Takes good care of her friends. Cons: Has a bit of a temper. Can cause trouble by taking jokes too far.