A Hero Who Knows His Stuff Manhwa

After spending 20 years fighting monsters in another world, Hyeonseok saves it and is sent back to Earth as his reward. Once a deliveryman named Chanseok, he expects to enjoy the comforts of modern life, but finds that Earth has changed in his absence. Monsters now emerge from randomly appearing Erosion Points, and people born with special abilities become Hunters to fight them. Chanseok reluctantly applies to become a Hunter, mainly because he wants the money. Having saved a world once already, he wonders how difficult it can be to do it again.