The 13 episode Overlord anime series aired during the summer 2015 TV season, but first came this novel (the first of 10 to date) by author Kugane Maruyama . It was originally published online in 2010 and then received some revisions for a formal printing under Kadokawa 's Enterbrain label in 2012. Now it is available in the States in hardbacked form, courtesy of the Yen On imprint of Hachette Book Group.

For those unfamiliar with the anime series version, the story is a mix of both the “ordinary person transported to another world where they are Someone Special” and “trapped in a game” gimmicks, in that both seem to apply but which is the actual, full truth is unclear. Is the world that Momonga has come to merely a world where the physics are based on game mechanics similar to the game Yggdrasil, or is this an actual case of the game world coming to life? Or has someone from Yggdrasil - as Momonga is beginning to suspect – come here before and set things up that way?

Whichever is the case, the weird way that the game mechanics interact with the fantasy settings is one of the story's most interesting aspects. For instance, Momonga's underlings in Nazarick all behave as if they have always been aware even though – from Momonga's viewpoint – they only became alive when whatever happened that put him in this situation happened. That includes being aware of the fact that Momonga's guild mates created them and have left for (in their understanding) parts unknown. This aspect gets most intriguing in an intermission scene after Momonga meets with all of them, where they all talk to each other about Momonga and consider the possible merits of Momonga siring a successor whom they could eventually pledge loyalty to, too (never mind that he's a skeleton!), and in one late scene where they try to deduce Momonga's motives from what he's said in the past and how he's acted. That these and other characters seem to be familiar with some game concepts but not all of them is a puzzle that remains not even close to solved at the end of the novel.

The story's other distinctive aspect – and the one that most gives it separation from similar titles – is its deliberate, measured approach. Momonga doesn't take anything at face value; he treats everything seriously, always assumes the worst, and thus plays very, very cautiously. The novel is meticulous in its descriptions of the precautions he takes, including how he interacts with his subordinates. Sometimes they still take him aback – such as Albedo's obsessive declarations of love, which he feels guilty about since he had muddled with her character background right before the game ended – but he always makes a specific effort to put on a lordly demeanor. (One of the running jokes of the novel is that he has far too little confidence in the overwhelming impression he's making on them.) Even when he forays out to the village that's being attacked, he acts systematically and tests everything as he goes along. Only once he understands that he's vastly overestimating the power of the forces arrayed against him does he start having a little fun with the role he's in. After all, being an undead Overlord is so much better than the office drone he used to be, and he doesn't really have any compelling reasons to go back to the normal world anyway. Ultimately he's only really interested in finding out if others have come to this world, too, and if any of them are his former guild mates, hooking up with them.

For those who have seen the anime version, the first novel exactly equates to episodes 1-4. It covers nearly all significant scenes from the novel without taking any real liberties, though it cuts down on the introspection by side characters outside of Nazarick, summarizes certain things, and reorders the placement of certain flashbacks. The main things that the novel can offer that the anime does not are greater insight into who Momonga was in his original world (it even gives his real name at one point) and expanded views of some of the game mechanics, such as Momonga marveling at how certain spells behave a bit differently in this setting even though they do still work. The effect that seems to be regularly calming Momonga in the anime version also gets a better explanation here.

The writing style is straightforward and easy to follow, though the translation makes some curious choices; the phrase “down low” used as slang appears multiple times, for instance, and seems a little out of place with the writing style each time. The book otherwise gets the professional, deluxe treatment, with a bold-colored sleeve and a trifold glossy sheet on the inside depicting Momonga and his chief underlings on one side and a breakdown of the Great Tomb of Nazarick on the other. Far less typically, it also provides color illustrations at the beginning of each chapter and in the Character Profiles for Momonga, Albedo, and Aura and Mare (which give relative power levels and partial class breakdowns) at the end. I must say that I am not a fan of the art style, though, for while it is striking, the details are too hard to make out in the busier scenes. Following the profiles are two pages of author's Afterword and one pages of author/artist profiles, which strongly suggest that Maryuama used his own situation with his declining tabletop RPG group as the inspiration for the story and outright indicate that the changes from original Web novel to conventionally published form were significant (though he does not provide specifics).