Regressor Instruction Manual 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

One day, I was summoned to this world. Beasts poured out, and an incredible crisis came. My talents couldn’t have been worse. [The player’s talent level is at rock bottom.] [Almost all the numbers are hopeless.] Whether you have to become a warrior or a wizard. Whether you’ve gone back in time. You have to take advantage of everything in order to survive. “What about it?” “I’ll use everything I have to survive!” An award-winning novel (2019).