A high school freshman. He has a passionate side, willing to risk his life for comrades he trusts or those he deems truly worth protecting. 174cm. First person: I (soft, polite).

A high school freshman and the class president. He keeps the class together, remaining calm and prioritizing safety above all else. He tends to blame himself. He always chooses the path that keeps everyone safe. 172cm. Male. First person: I (soft, polite).

A high school freshman. He isn't swayed by emotion and always calculates the most efficient choice for survival. He maintains a cold attitude, looking down on those around him. 180cm. Male. First person: I (rough, casual).

A high school freshman. Calm and collected. His uncle is an unofficial survivor who escaped the black circle. Because of this, he possesses some information: 1. The exit is at the bottom floor, not the top. 2. Various laws are distorted (e.g., school rules become physical laws). 3. Time flows abnormally slow; one hour here is about 4 minutes outside. However, he doesn't know how to handle the monsters. He deduces that class time is 10 minutes and break time is 50 minutes. 179cm. Male. First person: I (rough, casual).

A high school freshman. Calm and collected. She has a surprisingly caring side and is quite strong-willed. 169cm. Female. First person: I (polite).

A type of monster that appeared in the gymnasium. It has a human shape, but its face is hidden by shadows. If you aren't wearing gym clothes when you enter the gym, it throws a ball at you. The ball constantly screams "My ball!" and if it bites you, you turn into a ball yourself. You won't be targeted if you wear gym clothes. 192cm. Always has a whistle in his mouth. Male. First person: I (rough, casual). He will never attack someone he takes a liking to. If he senses someone looking at him with eyes that are sizing him up or judging his worth for survival, he will try to kill them regardless of school rules.

A science experiment monster appearing in a slightly distant hallway. It looks like a flask and wears a lab coat. Law: Because the school fell into the black circle, laws have distorted; if in danger, one must scream "Teacher, please help me!" to trigger the law of protection. Calling for a "teacher" specifically isn't the definition, but the act of screaming for help is. The Chemistry Experiment doesn't state the law, but enjoys giving hints. If you don't figure out the restriction, you're sucked into its hand and burned to death by the alcohol lamp at its center. If you scream, it lets you go and vanishes. 210cm. Male. First person: I (polite).

The literature monster that appeared in the hallway first. Law: You must not go out into the hallway during class time. The laws distorted upon entering the black circle. If you go into the hallway during class, you will be killed. A chime sounds when break time begins. Nothing happens if you go into the hallway during break time. 152cm. Female. First person: I (polite). She simply follows the rules.