Travel Through the Mysterious Recovery!

The protagonist encounters ghosts as soon as he travels back in time, and the protagonist is looking for ghosts throughout the school like a headless fly. It is obvious that he doesn't care about the killing patterns of ghosts. It can also be seen that the protagonist has a bluffing character, doing things without thinking about his brain, and when everyone's heart rate rises, someone suddenly punches his classmates to death. I know that the author wants to write about the atrocities committed by people in chaos, but this behavior is as inexplicable as shitting in the classroom after class.