Mirage is a Manga/Manhwa/Manhua in english language, SCI-FI 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

Han Nari is a high school girl, who knows every strategy for all the games in the world and is practically a pro gamer in theory. Her brother, Han Haeun, might seem like an ordinary student, but in the gaming world, he’s unleashed without limits. These siblings combine their strengths to flawlessly conquer ‘Mirage’, the virtual reality game. But there’s something unusual about these games. They experience pain in the virtual world just as they would in reality. And in a horror game, no less?!