According to the author himself , Kugane Naruyama , volume 17 of the Overlord light novel will conclude the series. This volume is scheduled for release on March 12th .
The author had previously hinted on his Twitter that he intended to finish the work in volume 17.
Overlord also received a successful anime adaptation 2015 , with the first season consisting of 13 episodes .
All three seasons are officially available on Crunchyroll a fourth season has already been confirmed
Source: ANN