Before the apocalypse, the world had hunters ok?
Hunters existed and dungeons existed
That huge monster was a dungeon boss of an SS rank dungeon that was able to get out due to a supernatural phenomenon called "dungeon break" im sure you know what that it but in this context, it is when a dungeon boss isn't cleared but has people entering and has people experiencing many trials and errors
Basically if you enter a dungeon there is a time limit put on it and unfortunately no one in Korea was strong enough to put a stop to it. Most hunters work for money so…yeah. They don't tend to give a shit about the peril their country is going through especially if a big powerful country wants them
The monster was defeated but not by the hunters.
The day the monster died was the day that dungeons stopped existing
And before the apocalypse, Hunters didn't have superpowers, they had skills.
After the apocalypse, Skills ceased to exist
If the hunters had any skill that enhanced their mind, body, emotional state then their current body wont return back to how it was before but all their skills will vanish
But they will just be better than the average human and have a stronger boost
Just to clear up any misunderstanding