Rental Hero

Juwon Lee works as a doppelganger who poses as a hero's alter-ego, and fills in for them in their social life while they perform their duties as heroes. One day, Justice, the strongest hero, approaches Juwon and requests his services with the promise of a hefty payment in return for his work. However, when Juwon arrives at their meeting spot, he is instead greeted by a completely unexpected sight...

(Source: Webtoon Entertainment)