Dungeon Preparation for High School, Class D Is All Anomalies

[The dungeon of Skyfall is coming + campus life + problem children + funny and funny + cp + single female protagonist + growth flow + daily life. ] Eleven years ago, the boundless sky suddenly enveloped Blue Star. A light blue wall of light cuts off the sky, reality and a copy of another space forcibly overlap, and apocalyptic changes sweep across the world. When the dungeon arrives, life and death are no more trivial matters. Stepping into it is a real game of life and death, and falling means permanent death. After four long years of panic, chaos and fighting, mankind was forced to recognize the reality. In order to stabilize the foundation of human existence, the world joined forces to establish the Sky Curtain Management Bureau seven years ago. Build multiple replicas around the world to prepare for high schools. The three years of high school are three years of trials, and they are the watershed that determines class, life and death, and value for the rest of your life. All school-age teenagers are compulsorily enrolled in the school, and the grades are divided into four classes: A, B, C, and D. Resources are skewed, strengths are stratified, and the rules are strict. Everyone is vying for spots in Class A and Class B, but Class D is the only one recognized by the whole school as a shelter for troubled children...