After a Game Dungeon NPC Awakens

No CP + a touch of horror + pseudo-infinite flow + secret identities Chu Qi always thought her life was just that of an NPC following a script. It was peaceful and uneventful, until this day in her senior year of high school. The cycle began. Every month, new faces would appear in the classroom. Before long, they would vanish without a trace, as if they had never existed. Full of questions, Chu Qi began to investigate. Strange things kept happening in the classroom. And yet everything around her seemed perfectly normal?