The Postman of the Apocalypse

A brief description of the manhwa  The Postman of the Apocalypse:
Destruction has become everyday life.
The chaotic period right after the apocalypse—when slaughter ran rampant—has long since passed. That doesn’t mean the killing has stopped, though. Corpses still overflow everywhere, but there’s no one left who thinks of this world as chaotic anymore.
That’s what “everyday” means. Nothing strange about it. Ordinary. Normal.
Yes, this is an ordinary story