Kono Sekai ga Game da to Ore dake ga Shitteiru  

Only I Know That This World Is a Game, この世界がゲームだと俺だけが知っている

Nekomimi Neko Offline, also known as New Communicate Online, is a virtual reality game that's popular for its numerous bugs. The protagonist of the game, Sagara Souma, is an avid fan who gets sent to the game world by a mysterious device. Despite being taken aback by the sudden change in circumstances, Souma quickly adapts and uses his knowledge of the game's rules to overcome every obstacle he encounters. As a result, he becomes known as "Maverick Swordsman Souma," renowned for his ability to exploit bugs and use them to his advantage.