Emperor of Steel 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

Seymon, the supreme ruler of black magic, who was once called the Demon King, was slain by the hero named "Lakan" under false accusations. However, when he opened his eyes again, he was already five hundred years in the future. And this time, he was reborn as a descendant of Lakan.