The afterword to the second part of the 16th volume of Kugane Maruyama 's light novel , Overlord , revealed that it will end in two volumes.
Synopsis
Yggdrasil is a popular online game that suddenly has its servers shut down. Momonga, a young player, decides not to leave the game and is transformed into a skeleton, the Overlord. As he has no family, friends or place in real society, young Momonga decides to fight to dominate the new world that the game has become.
Kugane Maruyama began the original light novel series online in 2010, and Kadokawa 's Enterbrain began publishing the series in print with illustrations by so-bin in 2012.
Source: ANN