Marble Room ni Tojikomete

Marble Room ni Tojikomete is a Manga originally published in Seijin manga magazine. The story revolves around a high school student who discovers a mysterious room in his school that appears to be a miniature replica of the world, with its own laws of physics and a mysterious marble that holds the key to manipulating reality. As he delves deeper into the room's secrets, he must navigate the complex relationships between the room's inhabitants and the consequences of altering the world's course. With the marble's power comes great responsibility, and the protagonist must confront the ethics of tampering with the fabric of reality.