The Scumbag from the Future

Just like the title says, this is about how a man from the future gradually becomes a scumbag in modern society.

Time travel, a return to school, mysteries emerging, reality changing.

The bleak truth and the helplessness of the future: all are games played out beneath the passage of time, and no one can change them.

This is a somewhat mind-bending story set in the real world, told in the third person from the male protagonist's perspective.