The Extra is Too Strong 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.nl fastest updating comic site. The Summary is

I received the same question every day, but the answer never changed. The only things I had left were sympathetic gazes and the monthly insurance payments. And the cruel reality of being half-paralyzed. They say that God only gives you trials you can endure, but I would rather have died. That was when I woke up— [This is the world of the “Magician Who Dominates the World.”] [From now on, you must live as the character “Mord Vernars.”] I became an extra in the novel I was reading overnight