Overlord is a Japanese light novel series written by Kugane Maruyama and illustrated by so-bin. It began serialization online in 2010, before being acquired by Enterbrain. Thirteen volumes have been published since July 30, 2012. A manga adaptation by Satoshi Ōshio, with art by Hugin Miyama, began serialization in Kadokawa Shoten’s manga magazine Comp Ace from November 26, 2014. Both the light novels and the manga are licensed in North America by Yen Press, with a release date of November 8, 2016.
In June 2015, prior to the release of the anime and manga, the light novel series had about 600,000 copies in print in Japan with eight volumes. By August 1, 2015, the light novel and manga series had a total of 1 million copies in circulation in Japan. On August 4, a 600,000-copy reprint of the novels was announced. As of August 20, 2015, the nine-volume Overlord light novel series and two-volume manga series have, together, more than 1.5 million copies in circulation in Japan. As of September 18, 2015, Overlord light novel and manga has over 2 million copies in circulation. As of May 2016, the Overlord light novel series had 2.5 million copies in print. Overlord has since been named the top-selling light novel series of 2015. As of April 2018, the light novel and manga combined had over 7 million copies in print.
The light novel ranked first in 2017 in Takarajimasha’s annual light novel guide book Kono Light Novel ga Sugoi!, in the tankōbon category. It ranked fourth in 2018.
In reviewing the anime adaptation, Kotaku called the Overlord anime a “magnificent power fantasy” which “brings up a very relatable theme for anyone who has played an MMORPG before.” However, a review by Monsters and Critics claimed that “fans were not too happy with the CGI animation” produced by studio Madhouse for the third season and the “biggest disappoint was Overlord Season 3 Episode 12, which animated the epic scene showing the Dark Youngs.”
In the year 2126, a Dive Massively Multiplayer Online Role Playing Game or DMMORPG called Yggdrasil was released. It stands out among all other DMMORPGs due to its unusually high ability for the player to interact with the game. After an intense 12-year run the game servers are about to be shut down. Within the game exists a guild, Ainz Ooal Gown, once consisting of 41 members and credited as one of the strongest guilds in the game. Now only 4 of the members remain, the other 37 having quit the game. Of those 4 only one, an elder lich character named Momonga, continues to play as the guild leader and maintaining their headquarters, The Great Tomb of Nazarick. He invites the remaining guild members but of those only one appears and only for a short while before leaving. While saddened by this, he accepts the reality that his friends have their other lives (both lives are real) to take care of and decides to stay logged in until the servers shut down.
When the shut-down time arrives, however, Momonga finds that the game hasn’t vanished. Instead it appears as if Yggdrasil has been recreated as its own reality along with its various NPCs having been brought to life while Momonga has been trapped in the form of his game avatar, leaving him unable to use the normal player functions, such as General Message, or even to log out. With no other option, Momonga sets out to learn if anyone from the real world is also in this new world with him. Taking on the name of Ainz Ooal Gown, a message to any other players, Momonga begins exploring the world in an attempt to figure out what has happened while searching for anyone or anything that could help him solve this mystery, while ensuring the safety of Nazarick.