Naega Kiun S-Geupdeul

Yu-Jin is an F-ranker overshadowed by his little brother, an S-ranker. All he does is get in his brother’s way, causing trouble wherever he goes. When a seemingly routine dungeon raid goes wrong and costs Yu-Jin his brother’s life, Yu-Jin decides to use the wish granted by clearing the dungeon to reset his timeline. The plan was to lead a quiet life from now on… but now it turns out he can help other people become S-rankers?! Maybe this is Yu-Jin's chance at building his own entourage of powerful metahumans… but it may be easier said than done.

(Source: WEBTOONS, edited)