Reincarnator (Manhwa) is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

[Adapted from one of the old top novels of all time!]

God created the Abyss to escape his boredom. Trapped in the hellish Abyss, humanity was on the path to the apocalypse… “Is it over for us… now…” On the brink of humanity’s annihilation, the four strongest survivors tried to prevent it by traveling back in time to the point just before humanity was pulled into the Abyss. But only one of them could go back to the past. “What’s there to think about? Isn’t it already decided who’s going? The strongest among us, Kang Hansoo.” This is the story of the life of the legendary powerhouse, Kang Hansoo, who returned to save humanity from its doom. Will he be able to save everyone?