The Iron-Blooded Necromancer Has Returned is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here.
Hela, a world of relentless killing, war, violence, and murder. Kang Hyuk awakened as a necromancer in this world. He did not know why or what had caused it. Was it because he had encountered death too many times? Six years after his brother returned to Earth, Kang Hyuk had become the ultimate necromancer and received troubling news, “My liege, I have something urgent to tell you. Your brother, who returned to Earth, has died.” Kang Hyuk’s future was thus set to return to Earth as he vies to obtain vengeance for the death of his brother.