Amazon's listing of the 14th volume of Midori Amagaeru and Kyokatsukasa's Online: The Comic manga states that the manga is approaching its climax and will end in the 15th volume. Shogakukan Creative will publish the 14th volume on December 11.
The manga launched on DeNA's MangaBox app in 2013. The English version of the app, which also launched in 2013, also published the manga digitally in English, until MangaBox discontinued its English app. MangaBox describes the story:
Mai Yashiro (22) was an average office worker until the day a video game console arrived in her mailbox. The game she is forced to play, “Nightmare,” is a dangerous game in which one risks both the lives of the ones they love and their own body!! If you refuse to play, those dear to you die. If you lose battles in the game, parts of your body (your arms or legs, your voice, etc.) cease functioning. The horror of this game spreads throughout society in a flash, and, to fight it, Mai's company creates a “Nightmare” Strategy Team. After being assigned to this team, Mai and her dependable comrades boldly rise up against this hellish game. Adapted from the super-popular novel which has received over 40,000,000 hits online!!
Amagaeru launched the original novel series in 2011, and Kadokawa published the 20th volume on June 12.