Moon-Shadow Sword Emperor 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

“What a dogshit life… honestly.” Though he had become a disciple of the Heavenly Demon amidst the strife-filled Demonic Sect, Yeon So-Woon gets betrayed by his disciple-brother and comes to meet his end. However… When he woke up, he’s back to the time when he was a kid, before he got dragged into the Demonic Sect?! Loath to repeat his hellish life in the Demonic Sect, Yeon So-Woon begins to plan for his new life. I’ll enact revenge on the Demonic Sect, Become an elder of the Murim Union, And thus, live a prosperous and respected life.