Did the human body of Momonga transform itself into his character in the game? If that's the case, his soul should be in this character.
Or is it something similar to SAO in which his original body is still in the "human world", but his soul (or consciousness) in the "game world"?
Or could it be that Momonga is with his soul and human body in his own world and sits in front of his computer playing this realistic game?
He's definitely transported into the game, unlike in SAO, all the game features are gone, if you'll recall in the first couple episodes, he has to adjust to his powers and how to use them. In SAO even though they were "full dive" they still played it like a game, while in overlord it was more, this is real life, not just a really realistic video game.
Ainz was transported to a new world, some say he was transported because of wild magic, but the wild magic for some reason believed his avatar was his real body.
There are some hints as this in the beginning of the light novel that leads you to believe that it isn't like SAO.
There are some other parts that explain this a lot better than I can. Not only is there a Light Novel, but there are a lot of secondary or mini Arcs that have other details. There is one which is some time after the game ended with a few of Ainz old guild mates talking in real life and some other details.
You can check with the overlord community on reddit and it is common understanding that Ainz is in a real world.
Theories about how players got there: https://www.reddit.com/r/overlord/comments/6q9g3i/yggdrsil_shutdown/dkvnj5y/?context=3
Wild magic and how it might work: https://www.reddit.com/r/overlord/comments/6tfawd/speculations_of_yggdrasil_and_nw_magic_possible/dlkxqwh/?context=3
in the LN it says this 'To date, this body of his had not felt thirst, so it did not bother him. Although he was well aware that the dead would not feel this way, he could not help but think this was all a joke once he realized that he was no longer human.' So we can assume his body no longer exists in the real world
Episode 1 start with an explanation that Yggdrasil (the name of the game) is a DMMO-RPG (Dive Massively Multiplayer Online Role Playing Game). So, basing my assumption on the word 'dive', I would say that the setting is somewhat similar to SAO.
The Momonga we see in the new world (new game) is an AI version of that player. Why bother with the far future? Why the differences he has noticed in his emotional make-up? My theory? He isn't "real". Free beta testers! – RichF
That is a great answer! It also explains so many other things, for example, the new setting appears to run on many of the same basic rules...with new options added, like marshal arts (and rune magic) that didn't exist (or weren't implemented, or were largely unknown to the players), in Yggdrasil. Also, there is mounting evidence...we even see plenty of it in the anime, that there have been other players in the new World...many, many years ago.
Momonga could have been sitting, as lifeless data on a hard drive, along with the rest of Nazerick, for all the years it took for true AI to come into being, finally, after loads of history takes place, often using rules that came into being long after Momonga was recorded, the Great Tomb is awakened and the Supreme One orders Sabas to scout the perimeter...
If he were still thinking using his human brain, back in his apartment, he would have passed out from low loos sugar and lack of sleep days before he even goes outside for his fateful Moonlight talk with Demugure.
On the other hand, maybe it is all just magic. Maybe when the Wild Magic event that created the currently popular forms of magic occurred, it copied the rules for how the system of spells would work from a computer game on a different World. When the game was copied, it was copied complete with the popular dungeons, like Nazarick. Another popular story, in the same genre ("Isekai"), which should also get an anime,"Kumo Desu Ga, Nani Ka?" (high school class becomes heroic princes and princesses...our hero, friendless gamer-girl becomes mook tier monster in a dungeon) eventually deals quite well with the often ignored question of why a real-seeming World would so closely resemble a game. I, personally, am very fond of how "Re:Monster" (govenment assassin becomes goblin, in goblin clan) handled it, too.
It is very, very common, right now, in Isekai stories, to have the new world the hero is reincarnated into be bizarrely similar to a "RPG" video game, to the point where everything runs on "Dungeons and Dragons" style rules, even when they seem ridiculous for a "realistic" fantasy world...when they seem like an approximate model of reality, that skips a certaint level of detail, rather than anything that would ever naturally develope. While this seems really odd to most readers/viewers who aren't used to it (English speakers), it is so much a convention, that the vast majority of the stories don't even question it, some of the best ones do. The two I just mentioned, and others; "Kono Subarashii Sekai ni Shukufuku" is a parody, and acts like a parody, "Youjo Senki" has divine intervention as part of the basic premise, "ErfWorld" had a magic spell looking for someone, somewhere in the multiverse who had a required aptitude with the way the World worked (so it grabbed a game designer who had made a similar game)...SAO tries to explain why people are "trapped in a game" and is EXTREMELY popular...but I feel it falls far short of Tad Williams' "OtherLand," but apparently popular audiences wanted a quick explanation, rather than clues dribbled out over five long novels.
Overlord might just leave the question unanswered, as so many do, and we will have to decide for ourselves. Momonga is certainly better off as Ainz-sama, than as "Sezuki Satori" in his crapy, distopian Japan, and I'd enjoy his story, in his New World, even if he, and we, never find out how it happened...I just hope we get more than just 12 new episodes, in this story (second season is happening, I'm so happy) because our World really needs the few truly great isekai stories, of which Overlord is definitely one, to become well known...because there are quite a few stories that aren't as good, and the genre is very popular, in some languages. The potential audience needs to see that modern popular isekai can be great.
He died. His soul just stayed in the full dive game.
It's kind of like what's happening in season 3 of SAO Alicization. Just he's actually dead and can't fix his brain. When it went all black and he said "I have work at 4 am", I figured he just died from over-exhaustion or he had a heart attack, otherwise why else would he go black for that couple seconds then come back. He died for sure.
He not dead the New World and Yardrasigil are completly different even the land and surrounding are not the same.I'm willing to bet that this is the result of a summoning type wild magic that existed in New World before and that magic creating a portal that summons a powerfull objects and people from Yardrasigil every 200-300 years New World time (since the game was only 12 year there is a difference in time space law) and since the magic was fixed to bascically what it thought was another world (Yggdrasil) it sensed that this world was coming to a end and pulled the last people it could find and their belonging and buildings. Buildings have been taken before such as (due to lots of speclation that holds a good probability in fact) that the floating building the Platinum Dragon lord building belongs to the Eight Greed Kings.
I for myself think he is dead. Even if his body in the real world is still alive when his consciousness were brought into the New World, I don't think his real body would have survived starvation without proper medical attention. Another possibility is at the moment when the clock hit 0:00:00, the device which he used to dive into YGGDRASIL malfunctioned, thus frying his brain resulting in instant death. There's millions of players in YGGDRASIL and certainly Momonga is not the only one waiting for the "force logout". Even 0.1% of 1 million players is enough to flood the New World.
My point is, since Momonga's real body was already dead when the clock hit 0:00:00, his consciousness (which was already in Nazarick) didn't have a body to return to, thus resulting in his consciousness staying in Ains' body. Because when you think about it, the Six Great Gods came into the New World 600 years ago whilst the Eight Greed Kings came 500 years ago, which means Ains' appearance is 500 years after the demise of the Eight Greed Kings. Something must have happened to their original bodies, too. Because if not, then who came 400 years ago or 300 years ago? It was never mentioned, right? That's because nobody else came after the Eight Greed Kings' death. It can be said that one of the conditions for being transported to the New World is that the player's real body must be dead.
