God-level Assassin, I'm the Shadow

In a world where people sleep and enter the realm abandoned by God, Qin Feng, who had sacrificed everything for his sister, is betrayed by her.
However, fate grants him a second chance, sending him back nine years before the abandoned world appears.
This time, Qin Feng chooses to abandon his sister and focus on becoming the strongest.

(Source: MangaUpdates)