The 100,000x EXP Transcendent Hunter

Ji-Han Lee is an F-rank hunter with no talent or skill, living in a world overrun by a demon invasion. And the demons are winning! Backed into a corner, humanity has no choice but to send a special hero back to the past to start over. But by a twist of fate, it’s Ji-Han who gets sent through the portal instead! Returning as his younger self, Ji-Han discovers that he’s been granted a special leveling trait that gives him a massive head start... but he still has a long way to go. Can Ji-Han, the F-rank hunter, save the human race?

(Source: WEBTOON)