School, but prison, madman, or non-human. The protagonist is also the final boss of the world. There is no redemption and can only rot together.
[A product of madness, don't take it too seriously. The protagonist's values do not represent the author's values, and the protagonist does not represent justice]
The world is a giant inverted triangle, and you and I are peeking into its original appearance while sinking
Idea: What cannot be done in reality can be pursued in another dimension. For example, you