The Main Characters That Only I Know 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

“If I were given another chance…” 10 years after the apocalypse began on Earth, while he faced imminent death, Yoohyun was filled with regret. Just then, a bright light descended upon him. When he opened his eyes, he was greeted by an unfamiliar scene… Not only had he reincarnated as a non-human race called “Teller,” but he had also traveled back in time by 10 years! “Now that it has come to this, I’ll live my best life this time!” Unlike his previous life, where he was solely focused on survival, he is now determined to lead a successful life. In this new life he has gained, will Yoohyun truly be able to become the protagonist?