Shadow Master -Gekka no Musou Geki-

Summary

Salt, a doppelganger boy, lived a life of persecution in the desolate slums known as the “Lost Area.” The one who saved him from his crushing loneliness was a girl named Rakuna. Through her, he finally found a semblance of peace—but it was not meant to last. Suddenly, a swarm of monsters appeared, slaughtering humans one by one. In the midst of the chaos, Salt watched helplessly as Rakuna was brutally murdered before his eyes. Driven to madness by despair and rage, the power sleeping deep within him finally awakened. After meeting Hakua, a mysterious girl who holds the key to changing the future, Salt travels back in time to reclaim everything he lost. To exact his revenge on the monsters and save the one he loves— The legend of the kind-hearted “monster” boy begins now. [Original Webtoon](https://jp.piccoma.com/web/product/208853)