The Novel’s Extra is a Manga in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.thenovelsextramangafree.com fastest updating comic site. The Summary is
Wouldn’t it be a dream to wake up in a world of your own creation? For Hajin Kim, it’s nothing short of a nightmare. With no clue how or why he’s been transported into his web novel—as a mere extra, no less!—Hajin has little choice but to see his story through until the end. Lucky for him, as the author, he knows this perilous world like the back of his hand. But when discrepancies in the plot begin popping up left and right, Hajin soon realizes that things aren’t quite so simple, after all…