Ainz Ooal Gown


 * "I will announce the goal for everyone turn Ainz Ooal Gown into an eternal legend. If there are many heroes, then we will replace them all. Let the entire world know that Ainz Ooal Gown is the true hero!"
 * - Ainz announcing his goals, setting all of Nazarick into motion

Ainz Ooal Gown (アインズ・ウール・ゴウン), formerly known as Momonga (モモンガ), is the main protagonist of the Overlord series. He is the guildmaster of Ainz Ooal Gown, Overlord of the Great Tomb of Nazarick and the creator of Pandora's Actor. He is regarded as the highest of the Almighty 41 Supreme Beings by the NPCs of Nazarick.

In the New World, he is the Sorcerer King of the Sorcerer Kingdom and the most powerful magic caster in the world. His other identity is famously known as Momon, a dark warrior and leader of Darkness, an adamantite ranked adventurer group of that nation. He is an adamantite class adventurer and the strongest adventurer in E-Rantel.

Appearance
Ainz Ooal Gown has the appearance of an Overlord, an undead skeleton creature who is devoid of skin and flesh. When exposing himself without any attire worn, his whole body alone is purely made up of just his bones overall. While so, Ainz tends to mainly wear an elaborate, jet-black academic gown adorned with golden and violet edges.

Furthermore, he has a type of tiny dark red glow radiating from inside the empty eye sockets. Sometimes however, that glow can become largely intensified, leading it to elicit faint red flames flickering about in his eyes. Additionally, Ainz has a dark halo-like object glimmering right behind his head.

In his dark warrior persona as Momon, Ainz would wear a fully jet-black body armour with purple and golden markings on it. Along with it, he also have on a red cape and two large swords on his back while carrying it behind him.

Personality
While being a cautious and stingy person, Ainz would always tried to plan ahead and control details beforehand in order to avoid any haphazard actions that can endangers Nazarick's existence. This means going so far as lying to the inhabitants in the New World that he can't used one of his Super-tier spells for years to come after using it once. Since being transferred to a new world and becoming an actual undead being, Ainz could feel himself becoming very cold and calculating while his emotions repressed.

While being the guildmaster of Ainz Ooal Gown, he loves to reminisce about the wise words from his fellow guildmates as they may hold some meaning now in the new world, which the NPCs wholeheartedly agreed too. As he is loyal to his friends and the NPCs created by them, he then acts with a certain degree of nobility, when leading his devoted followers properly, seeing him in the image of a divine entity. It was so they can faithfully have a Supreme Being to look up to and depend on since he is the ruler of the Great Tomb of Nazarick and the last Supreme Being to have stay with them even after their creators have left them behind. He is caring for them like a father figure would as Ainz tries to act that way for Pandora's Actor and his friends' NPCs.

When he was crowned king of his newly-formed country the Sorcerer Kingdom, this trait also plays a certain key role in earning loyalties among his countrymen. For instance, the Guildmaster Ainzach describes Ainz as being a rational person who makes wise decisions carefully, commending him to be an intellectual, but merciful ruler. Additionally, Ainz is open-minded to others' opinions of the actions he has partaken, appreciating their criticisms and learning from his mistakes, in which the Floor Guardians couldn't do to help him.

Furthermore, Ainz is not only look upon as a thoughtful and generous person, but also by the people who work for him while kindly rewarding them with YGGDRASIL items due to their hard-work. At the same time, Ainz is true to his words and oath, when he honorably accepted certain conditions made by individuals in the form of promises held to a high degree without betraying them. He has a benevolent nature of ruling over his nation peacefully without bloodshed, figuring there is still always room for reasonable negotiation. Yet at times however, Ainz would feel paranoid and pessimistic that his Floor Guardians or other NPCs that follow after them may someday abandon him if he doesn't lived up to their expectations.

He only does things that will benefit Nazarick or himself above all else, whether its information or prestige. Although he does have a sense of justice and doesn't hate humans as much as his followers, Ainz holds no deep attachment to them, and he feels nothing toward their deaths. Ainz did not view humanity as an enemy, but he could kill human beings with no hesitation for the sake of his goals. Even so, he wanted to avoid conflict with other players especially the ones who are human that would protect their kind. After killing Shalltear with his own hands, he became a lot more vigilant and hostile against players or other foes with World Items that could possibly harm Nazarick in the near future. Aside from the NPCs of Nazarick, the only players Ainz will show most concerned for were his past companions.

On the other hand, Ainz has a competitive side to him, regarding the actions of players within the new world was what motivated him to not fall behind in terms of technological development. Likewise, everything he does was all for the sake of Ainz Ooal Gown, the Great Tomb of Nazarick, and the Sorcerer Kingdom altogether. For that reason, Ainz is secretive about the information he may have gain, refusing to disclose anything in case it serves Nazarick's interest. Since Ainz prioritizes knowledge as an utmost importance to him, he also likes to participate in doing random experiments. With the sole purpose of obtaining valuable information on the New World's inhabitants, martial arts, magic, items, or even their way of life such as religion.

In his dark warrior persona as Momon, he is viewed by people to be very dignified as a worthy adamantite adventurer yet not willing to make others uncomfortable around him. True to his nature, Momon is also very faithful and honorable, when he refused Nfirea's request for the Swords of Darkness, prioritizing them first as it was something he accepted before anything else. While he holds great trust with his comrades, he refuses outside aid if they happen to slow him down during his job. Let alone that, he would used some of his spare time to exchange greetings with every single adventurer's group in the Re-Estize Kingdom. Out of respect for his fellow adventurers, he doesn't like to reap the rewards for himself and want them who took part in stopping the disturbance within Re-Estize to be pay equally as well.

Background
Before taking on the name of Ainz Ooal Gown in the new world, Momonga was his original name as a player in YGGDRASIL. While in reality, he was a human being by the name of Suzuki Satoru, his true identity. Somewhere during his lifetime, Suzuki lost his mother due to fatigue as she worked herself to death. Her death occurred in the kitchen of Suzuki's home, where she collapsed while pushing herself to make his favorite dish. He vividly remember seeing it happen with his own eyes in the morning upon waking up.

When Suzuki Satoru first started playing YGGDRASIL under the name of Momonga, he was very close to quitting the game. This is because of being discriminated as a member of the Heteromorphic Races that Momonga is hunted down by PKers in groups. Therefore, Momonga himself was seen by other players as a monster who only exist to be killed. However, he was then saved by Touch Me. Since then, both Momonga and Touch Me together made friends with seven others like them to form the First Nine, who started out the PVP/PKER clan, known as the Nine's Own Goal.

After the dissolution of the clan, Nine's Own Goal, however, Momonga now becomes the guildmaster of an official guild called Ainz Ooal Gown upon Touch Me's recommendation, which everybody agreeably accepted. Although Momonga was in the position of a Guildmaster of Ainz Ooal Gown, what he actually did was miscellaneous work like contacting people.

After the guild was created, Momonga would later lead Ainz Ooal Gown and its members to a dungeon called the Great Tomb of Nazarick. Due to Momonga's leadership and cooperation with his guildmates, it led to the guild being able to conquer the Great Tomb of Nazarick and shortly afterwards, also acquiring a World Item called the Throne of Kings the same moment they cleared the dungeon. The dungeon would later serves to be Ainz Ooal Gown's future guild base while dealing with the invasion of players intruding on their location.

Henceforth, the other players started to perceive the guild of heteromorphic races as evil beings that must be defeated at all costs. This way, the guild members of Ainz Ooal Gown including Momonga thought that it was only proper for them to become real monsters. It was indicated during the players' invasion of their guild base that Ulbert suggesting they should also act as final bosses unless the enemies are able to reach them.

During those years, Momonga and his guildmates spent most of their work and effort focus on building their guild weapon known as the Staff of Ainz Ooal Gown. In addition to that, Momonga and his guildmates created their own customized NPCs, which for him was Pandora's Actor. He made Pandora's Actor to not only preserve the identity of Ainz Ooal Gown, but to serve in protecting the guild's treasury for starters. At some point in time however, nearly 37 out of his 41 guild mates quit the game altogether, leaving the guild and giving away their player's equipment to Momonga. Not just quit the game, but as well as deleting their character's avatar completely due to real world issues his guild mates had to deal with. He would later stored most of his guildmate's equipment into the treasury for safekeeping. Momonga also made all of the Avataras in the image of his guildmates, who quit the game.

Ever since his guildmates left, Momonga had begun solo hunting areas and farming for things by himself to a nearly ridiculous degree to earn the gold needed to maintain the Great Tomb of Nazarick. The dungeon seems to be on top notch shape according to Herohero as he apparently taken notice of Momonga's efforts done to manage it alone as their guildmaster. Because of that, he did not bother to build new friendships with other players and avoided them, as well as the high-difficulty areas he used to visit when his guild members had still been around. Then, he would deposit his earnings in the Treasury before logging out. This had been his routine for almost every day. As such, he did not have much contact with the NPCs.

When his guildmates were still around, Momonga would return straight home after work, log on ahead of everyone else. Afterwards, he would then summon undead to protect himself and hire NPC mercenaries to hunt monsters. So technically speaking, he was used to playing alone and this holds true even until now after they quit the game.

Nonetheless, the tedious labor Momonga has spent while maintaining their guild base financially have managed to paid off as no players were still not able to conquer the Great Tomb of Nazarick even until the game is finally shutdown. This also applies to the amount of times and efforts he put forward into the game to prevent the guild's rank being formerly 9th from dropping any further than 29th as its current ranking. Strength-wise, Momonga did it all on his own as he was the only manpower who happen to be active daily within the guild.

Although all the other members had left, he still continue to stay behind and kept the guild's base running. This was so in the hopes that his guild members would one day return back to the game and played with him. Since Momonga doesn't have any real family or friends to support him outside the game, he dedicated his whole life instead to the game itself being YGGDRASIL and just his guild alone. Memories of the time he spent with his friends or guild members in Ainz Ooal Gown were all he had. Momonga's daily livelihood to the game has even go so far to the extent, where he used up most of the money financially obtain by him as a salary man in order to spend time playing it. In other words, Momonga has spent almost one-third of his monthly salary on cash purchases. This is because in real life, Suzuki Satoru was a salary man.

The Undead King Arc
Momonga, the guildmaster of Ainz Ooal Gown, was seen conversing together with Herohero during the last moments of YGGDRASIL before shutdown. Herohero would then bid farewell to Momonga and logs out for one and only last time as he has already quit the game. Mentally, Momonga is enraged about his friends leaving the game, but cools down after noting that they didn't abandon the guild - it was that they had real life issues to deal with. Still engrossed in the memories of the past, he takes the Staff of Ainz Ooal Gown before heading to the throne room.

Momonga encounters Sebas Tian and Pleiades at the Royal Suite and calls for them to accompany him. At the throne room, he discovers Albedo holding World Items. While he is initially irritated that her creator Tabula Smaragdina broke the guild rules, he quickly forgives him since Albedo was one of his treasured creations. Momonga looks through her settings and reprograms her to be in love with him. Without little time left, he sits at the throne and points at the banners, calling out the names of his guild members while waiting for the server to shut down. Unexpectedly, the server does not shut down and Momonga quickly realizes that something is wrong when the NPCs begin talking. Staying calm, he orders Sebas to survey the surrounding and orders Albedo to assemble the Floor Guardians at the sixth floor. Brooding to himself, he concludes that all of the NPCs have gained sentience and agonizes over Albedo's modified settings.

Momonga went to the Amphitheater of the six floor and meets with Aura and Mare. He asked the two that he is testing the Staff of Ainz Ooal Gown. After the experiment, he summoned the Primal Fire Elemental and asked Aura if they want to fight it which Aura agree and along with Mare. When they finished the fight, the arrival of the Floor Guardians started gathering one by one until everyone was fully assemble together and pledge their absolute loyalty to Momonga. Upon confirming their loyalty, Momonga went back to the Throne.

While so, Demiurge, who spotted Momonga trying to leave the area request him to be his accomplice outside of Nazarick to see the New World. After seeing the new world, he went to Mare and reward him the Ring of Ainz Ooal Gown for doing a splendid job and he also gives a ring to Albedo too then teleport back to Nazarick. Momonga using Mirror of Remote Viewing discovers a village being attack by knights. At first, Ainz doesn't want to get involved in the conflict, but when reminiscing about Touch Me, who had once saved his life however, he decided to saves the village. He then teleports to the outskirt of the village and saves Enri Emmot and Nemu Emmot, who are being chased by the knights. After saving them, he summons the Death Knight and orders it to kill the knights attacking the village. He saves Carne Village and gather information about the New World from the village chief. He decides to withdraw, but was soon confronted by Gazef Stronoff and his warrior troop's arrival at the village. He introduces himself as Ainz Ooal Gown who save the village from the knights. After he was thanked by Gazef, his subordinate inform him that the village is surrounded by unknown figures.

Ainz seeing that the unknown figures have Archangel Flame with them that similar to YGGDRASIL monsters. He realizes that Gazef is their target and he gives him a sculpture for good luck on his battle. All of a sudden, he magically switches place with Gazef due to that item's power and faces the Sunlight Scripture led by Nigun Grid Luin in his stead, and offers them the chance to surrender with their life or face death. He uses Negative Burst on the Archangel Flame, then uses Hell Flame on the Principality Observation and finally uses his Black Hole on finishing off the Dominion Authority. He easily defeats the Sunlight Scripture and went back to Carne Village to check Gazef's condition before leaving the village. After returning to Nazarick, he announces to his NPCs that he will no longer go by the name of Momonga, but calling himself Ainz Ooal Gown from now on, ordering them to make his new name an eternal legend to the New World.

The Dark Warrior Arc
Ainz Ooal Gown alongside Narberal Gamma goes under cover as adventurers under the alias of Momon and Nabe. They infiltrate the fortress city of E-Rantel and register as copper class adventurers. They cause a commotion at the inn which led Momon to gives Brita a potion for compensation. He discuss his plan to Nabe about their objective in this city. He plans on becoming famous adventurers and gather information about this world. They went to the Adventurer's Guild to search for a job and the group ended up meeting Swords of Darkness, whom offer him and Nabe a job. After the discussion, the female receptionist informs Momon that someone else request him for a specific job. As a result, he confronted Nfirea Bareare, who request Momon to be his escort to Carne Village while gathering herbs along the way. Nevertheless, Momon accepts both of their requests and their journey begins.

As they travel to Carne Village, the party is attacked by a large group of goblins and ogres. A battle plan is formulated quickly whereas the Swords of Darkness is in-charge of fighting the goblins, Momon and Nabe will be the ones who deal with eliminating the ogres. As the fight proceeds, Momon kills some ogres while Nabe finishing off the rest. The journey proceeds smoothly after the encounter, but things are amiss as Carne Village is more fortified than usual. Sensing that something is wrong, the party advances cautiously, but is ambushed by the Goblin Troop. Momon realize that the goblins in fact, turns out to be Enri's summoned goblin and she must have used Horn of the Goblin General for the sake of protecting the village.

Later on, Momon's true identity as Ainz Ooal Gown has been eventually discovered by Nfirea. This was due to leaving clues behind which the Nfirea was able to somehow piece things together in helping him realized who Ainz really is behind the adventurer persona. Thus, he apologized to Ainz for deceiving him and and wanted to thank him for saving Enri and Carne Village. Nfirea also tells Ainz, that the request was just his attempt to learn Ainz's secret of how he was able to make the rare potion. After convincing Nfirea not to revealed his identity any further, they went to the forest to gathered some herbs. Ainz orders Aura to lure out the Wise King of the Forest to him, so he can challenge him in battle. Upon fighting it however, he was disappointed that the Wise King of the Forest is actually a giant hamster all along and tamed it easily. Momon then showed it to the Swords of Darkness that he has the Wise King of the Forest under his control.

They return backed to E-Rantel, where Momon went to the Adventurer's Guild, so he can register Hamsuke as his mount and pet. Once Momon finishes Hamsuke's registration, he met up with Lizzie Bareare, grandmother of Nfirea, who led them to her workshop. He discovers that the Swords of Darkness are killed and turned into zombie. As a result, Momon was immediately left with no other choice, but to kill them, and begin investigating what had transpired while he was away. Momon finds out that Nfirea was kidnapped and tells Lizzie to hired him, so that he can save Nfirea. They went to the cemetery and breakthrough the mob of undead, and confronted the two instigator. He then have a one on one duel with Clementine and won successfully, finishing her off with a bear hug which led to her own death. After resolving the incident, he leave behind the enemy's corpses to the authorities as proof that they were the instigators. With the mess settled, Momon and Nabe are quickly promoted to mythril class adventurers. They returned back to the inn and discuss what to do with Nfirea and Lizzie. Suddenly, Ainz is informed by Albedo that Shalltear Bloodfallen has rebelled.

The Bloody Valkyrie Arc
After being informed by Albedo that Shalltear Bloodfallen has rebelled. He returns back to Nazarick, and finds out why Shalltear has gone rogue. He and Albedo went to the fifth floor to visit Nigredo and used her to find Shalltear. They discovers that Shalltear is now fully equipped in her Bloody Valkyrie form. However, Ainz is informed by Narberal that the Adventurer's Guild at E-Rantel is looking for him. He then went to the Adventurer's Guild meeting and discuss about a powerful vampire. Momon convinces and insists to the Guild leaders, E-Rantel's authorities and his fellow mythril adventurers that he will exterminate the vampire in sight. After the meeting and they went to the forest, he orders Albedo and Mare to dispose Kralgra, who ignored his advice and chose to follow.

He finds Shalltear and used Wish Upon a Star, a super-tier spell which failed to get rid of her mind-control. As a result, he assumes the worst from this experience and learning that Shalltear is under the influence of a World Item unknown to him. Ainz decided to retreat back to Nazarick and begin preparations in his fight against Shalltear. Ainz has no choice, but to get a World Item from the Treasury. He meets up with Pandora's Actor, his creation and the one who is in-charge of the guild's treasury. After talking to Pandora's Actor, he gives the Ring of Ainz Ooal Gown to him before entering the vault with Albedo. Ainz eventually decides not to use the World Items, since he didn't want to put it to waste and that he will face Shalltear alone without outside interference or help. Moreover, he handed some of those World Items to the Floor Guardians instead to protect them from the effect of their enemy's World Item. He then face off against Shalltear in an intense battle, using many of his spells against her. Finally, Ainz finishes her off with the super-tier spell, Fallen Down and thus, he emerges victories against Shalltear.

Returning back to Nazarick, Ainz resurrect Shalltear back to life and hoping that her death would cure her mind control which succeeded in doing so. He then started a discussion with the Floor Guardians about strengthening the Great Tomb of Nazarick's defense. While so, Albedo advises Ainz about the lizardmen might have potentially stronger bodies for him to create more, but powerful undead. At E-Rantel, Momon and Nabe are promoted to adamantite class adventurers after reporting on Shalltear's defeat.

The Sealed Evil Tree Arc
Ainz Ooal Gown once again using his adventurer alias Momon, to takes on a personal request from the Adventurer Guildmaster of E-Rantel. His mission is to retrieve a rare herb in the northern region of the Great Forest of Tob. Ainz is assisted by Hamsuke and Aura Bella Fiora who guides him to the location of the northern forest. The trio encounter a dryad, Pinison Pol Perlia. Through her, Ainz learns of the awakening evil treant, Zy'tl Q'ae.

Interested, he decides to go and investigate it despite the dryads warnings. Upon the group's entrance into Zy'tl Q'ae's lair, it has fully awakened and upon its head was where the herb they're looking for is located. Seeing an opportunity for an experiment, Ainz summons the Floor Guardians to do battle with the evil treant. Before the battle comes to an end, Ainz delivers the final blow against it and later returns to E-Rantel with the herb in hand.

The Lizard Man Heroes Arc
Heeding Albedo's suggestion from before, Ainz decided his next target will be the Great Lake. He orders Cocytus to annihilate the lizardmen and use their corpse to create stronger undead, so they would be able to strengthen Nazarick. While Cocytus has failed to annihilate the lizardmen, Ainz have planned it all along to help him grow individually. It was also just an experiment to use that weak army of theirs for observing how the lizardmen fight. He then changes his order from annihilation to occupation and for Cocytus's punishment is to be given control and responsibility over the lizardmen once they have submitted to Nazarick. Ainz and his forces confront the lizardmen and start a negotiation. He gives a condition to Shasuryu Shasha and Zaryusu Shasha, that they must face Cocytus in a battle. If they win, he will no longer attempt to bother them. However, if they were to lose or decide not to fight, they must readily submit to him.

Cocytus emerges victorious in his battle against the lizardman heroes. Ainz orders Cocytus to summoned Crusch Lulu to his presence. He suggests to Crusch Lulu to be his spy within the Lizardman Tribes in exchange for the resurrection of Zaryusu's life. After Zaryusu was revived, the lizardman now began seeing Ainz as their new God who not only has the power of death, but life too.

The Two Leaders Arc
Ainz took a bath by using the slime to wash and clean his bones. At the same time, he decides to invite all male Floor Guardians to enjoy the spa in the 9th floor together. In his bedroom, Ainz is practicing various different poses and speaking phrases. Ainz see Mare and asked why he is here. Mare responded that he's handing back the invitation that Ainz wrote. The two exchange words and Ainz ends up by expressing his love for the NPCs. Hearing what Ainz said, Albedo becomes unable to control her emotions and attempted to rape Ainz. Fortunately, he orders Mare and several Eight-Edge Assassin nearby to get Albedo off while punishing her to three days of solitary confinement.

Later that day, Ainz rides Hamsuke to the Adventurer's Guild headquarters in E-Rantel. He spotted Enri Emmot, who was about to be detained by the authorities. He comes and guarantee for her release from custody. Curious to the reasons, Ainz asked the Guild leader for the content of Enri's request, and finds out that it was relating to the lords of Tob Forest. Back at Nazarick, Ainz scolded Lupusregina Beta for not reporting to him and reminded her to ensure the safety of Enri, Nfirea and Lizzie Bareare.

Ainz along with Aura decided to meet the Giant of the East and Demon Snake of the West. He tries to negotiate with Goo, but it ended up in failure. As a result, he activated his Desperation Aura V and instantly kills Goo and his followers. Meanwhile, Aura captured Ryuraryus who pleads for his life and swear his loyalty to Ainz. He then began turning the corpses of Goo and his followers into an undead and use them to attack Carne Village. Back in Nazarick, Ainz consults Demiurge about the upcoming dinner that he will treat to Nfirea, Enri and Nemu Emmot. After that, Ainz and the male Floor Guardians begin taking a bath together. While Ainz stated that he has a good time in the bath, the Lion Golems attacks the female Floor Guardians to restrain their ignorant behavior. So Ainz and the male Floor Guardians prepare to help them, wishing for a peaceful bath next time if they were to have another one.

Nfirea, Enri and Nemu are invited to Nazarick to celebrate success of developing the new potion. Ainz requests Nfirea not to announce the existence of the purple potion after hearing about the attack on Carne Village. Thereafter, they enjoy the luxurious dinner of Nazarick as a reward from Ainz for their hard-work with making the potion.

The Dark Hero's Story Arc
Under his alias as Momon, Ainz was counting his saving and allocating the necessary funds to his various projects. He then later sent Narberal Gamma on an errand to collect ore samples for testing.

Later, he accepted a commission to guide a young noble named Torkel Karan Dale Völkchenheim and his servant, Andre to complete the former's coming of age ceremony. Ainz was initially suspicious of the human's enthusiasm and hostility. He believed that Torkel was an enemy luring them into a trap, but along the way he realized he was just another of Narberal's persistent suitors. On their way to the goblin village, the party encounter a Gigant Basilisk. Seeing the beast, Ainz ordered the group to run while he disposed of the creature. The battle was witnessed by Torkel who would pass on the tale to his future descendants.

The Men in the Kingdom Arc
and The Men in the Kingdom II Arc At E-Rantel, Ainz was planning on giving the Floor Guardians a reward for their work and loyalty. He then orders Narberal Gamma to buy and collect an iron ore from different locations, so that he can toss it in the Exchange Box. Meanwhile, he receive a message from Solution Epsilon that Sebas Tian has betrayed them. After being inform about Sebas's betrayal, he orders Pandora's Actor to transform as him and test Sebas's loyalty whether or not he really betray them.

After Sebas's loyalty has been cleared, Ainz teleports to the mansion and he recognizes that Tuare is the older sister of Ninya, and decides to accept her into Nazarick as a maid, and under the protection in the name of Ainz Ooal Gown. After returning back to Nazarick, he's inform by Sebas that Tsuare has been kidnapped which upset him greatly after swearing his name to protect her. He orders his subordinate to bring Tsuare back unharmed and destroy Eight Fingers.

To cover up the rescue of Tsuare and Sebas's identity, he takes on the persona of Momon while Demiurge masquerade a demon invasion on Re-Estize, so that it could help him increase his fame if the operation was successful. He also used Marquis Raeven's request as a way to visit the Royal Capital without garnering suspicions from the populace of that area on why he's here. He saw and saves Evileye from Jaldabaoth, a powerful demon lord, who besiege the Royal Capital by an army of demons. Jaldabaoth tells Momon that he came here to find an important item in the Royal Capital. Momon exchanges a few rapid blows with Jaldabaoth while protecting Evileye from one of his attacks, but the demon later made a temporary retreat.

Outside of the Adventurer's Guild, Blue Rose and Princess Renner, gathered all of the adventurers that were present within the city are order to counter attack and defeated the demon army led by Jaldabaoth. In their battle plan, the adventurer are the bow while Momon is the arrow as nobody except him can fight against Jaldabaoth. When the operation commence, Momon, Nabe and Evileye found him, who's waiting for them and suspected it was a trap. Momon tells Nabe and Evileye to handle Jaldabaoth's maids while he face off him. During their fight, Momon and Jaldabaoth crash into a building and walk into a secured room, where Mare was waiting for them. There, Ainz hears Demiurge's explanation about the plan to make Jaldabaoth as the "Demon Lord", due to one of Ainz's previous orders.

Following the plan, Momon confronted Jaldabaoth in a fierce battle and defeated him. Jaldabaoth proposes to Momon that he'll cease the fighting with the condition of allowing himself and his demon army to withdraw. After the withdrawal of Jaldabaoth and his demon army, Momon becomes a national hero of Re-Estize Kingdom.

The Invaders of the Large Tomb Arc
Ainz returns to Nazarick and gathers all of the custom NPCs in the Throne Hall, so he can grant honors to the NPCs for the successful operation in Re-Estize. After hearing Demiurge's plan, Ainz finally realized that the Floor Guardians are trying to take over the world without his knowledge. He has no choice, but to go along with their plan of world domination.

Following Demiurge's suggestion, he must find a country to recognize his new nation. Ainz and Narberal Gamma visit Arwintar, the capital of the Baharuth Empire to meet Fluder Paradyne, the strongest wizard of the empire. He meets Fluder and shows his true power to him. Witnessing his power firsthand, Fluder immediately swears allegiance to Ainz. He orders Fluder to send sacrificial pawns to the Tomb.

As Momon, he escorted the workers to the Tomb and prepares to monitor the massacre. Also, it was to test the Tomb's defense system if whether it was working or not. He choose Foresight as his sparring partner and sent them to the sixth floor, where he does battle with them in the Colosseum. Hekkeran Termite tries to deceive Ainz, but he sees through his lie and becomes really upset about it. After fighting with Foresight as a warrior, Ainz decides to stop playing around and reveals his true power, and instantly defeated them one by one. Although the members of Foresight manages to let Arche go ahead of them, her attempt to escape was a failure as she was killed by Shalltear shortly thereafter. After that, he orders Aura and Mare to visits the imperial palace with dragon and threatens the emperor if he does not apologize for the invasion, they will destroy the Empire.

The Magic Caster of Destroy Arc
In Nazarick, Ainz meets Emperor Jircniv and his delegation to officially apologizes to Ainz Ooal Gown. After Ainz accepted their apology, Ainz then turns Femel's corpse into a Death Knight right in front of them which causes the imperial delegation to feel terrified as he just created a Legendary Undead being with apparent ease. He agrees with Jircniv's proposal to form an alliance with him and Nazarick, and he also accept the idea of making his new nation known to the surface world.

After the talks were concluded, Ainz gathered the Floor Guardians in his room. Ainz explains to the Floor Guardians it is only to require a just cause and in order to avoid creating many enemies against them. He also explains to the Guardians that turning countries into graveyards will only damage the name of Ainz Ooal Gown. After hearing Demiurge's explanation to the others, he realized that Jircniv's intention was to form an alliance with the other countries to defeat him. Ainz then choose Cocytus's suggestion, he crowned himself as the Sorcerer King and tells the Guardians that he will demonstrate the power of Nazarick in the battle between the Kingdom and the Empire at the Katze Plains.

Ainz alongside Mare went to the Empire's Fortress at Katze Plains. They are welcomed by Nimble Arc Dale Anoch and General Carvain in the fortress to honor the alliance between the Empire and Ainz Ooal Gown. Ainz was requested by the Emperor to cast one of his powerful magic to destroy the enemy. Ainz tells General Carvain that his army will be arriving anytime. Afterwards, Ainz's army are teleported via Gate and he introduces his army to them which made everyone realize that the small army of five hundred is not to be underestimated.

In the Katze Plains, the Imperial Army started to separate into two flanks, effectively opening a path for the army of Ainz Ooal Gown. Ainz appears at the front of their army with Mare and Anoch standing at his sides, starts casting a single bright spell. Ainz surveying the area that there is no player in the Kingdom or no one is trying to stop him, Ainz cast the Iä Shub-Niggurath, consuming the left wing of the Royal Army and summoned five Dark Young. Ainz was overjoyed that he breaks a new record for summoning five Dark Young and ordered them to massacre the Kingdom's Army.

Ainz then takes off his mask and called upon the Imperial Army to cheer for his supreme power. One of the Dark Young was returning to Ainz and headed toward the Imperial Army's direction, which caused every single one of the imperial soldiers to run for their lives, trampling over their own allies. The Dark Young placed Ainz on top of its head and Ainz thought after casting his most powerful spell, the Imperial Army would charge in but seeing the carnage it was understandable that the Dark Young did all the work. Ainz then decided to continue his assault while Mare was left in charge with his army.

In the battlefield, Ainz sitting on top of the Dark Young came to greet Gazef Stronoff with Climb and Brain Unglaus arriving there too. Ainz then asks Gazef to be his vassal in exchange for stopping this war. However, Gazef politely decline his offer, and instead challenged Ainz to a single duel. Ainz accepted his challenge, and asked the two other people to be the witness of their match. Immediately after the battle starts, Ainz stopped time around them using Delay Magic along with True Death to kill Gazef instantly. Afterwards, Ainz tells Climb and Brain that he will stop the attack but demands them to cede E-Rantel and its surrounding area to him. Ainz then return back to the Empire's fortress with all of his monsters.

Later in spring, E-Rantel and its surrounding area became a part of the Sorcerer Kingdom. Ainz, Albedo and his army of death knights and death warriors enters E-Rantel. Albedo then decides to kill a young boy, who is disturbing their arrival march but was stopped by Momon. Ainz stops Albedo and tells her that Momon will serve him as the sword of the Sorcerer King, which Momon accepts his offer. Afterwards, E-Rantel became a peaceful city without bloodshed under the rule of Ainz Ooal Gown.

The Ruler of Conspiracy Arc
Once the war was over and E-Rantel came under the rule of the Sorcerer Kingdom, Ainz has established the city to become the new capital of his nation. Under his rule, he has to decide on how to procede from their in ruling his nation by implementing new laws, set up defenses, establishing a new governing body, all of which was a lot more than he could handle. In addition, he moved to the former Mayor's residence and set it up as his base of operations.

It was also around this time he took notice of the severe anxiety of the people of coming under the rule of an undead and with all the monstrous beasts that were coming into the city. He also noticed the sever absenteeism of adventurers having new quests or anything to do as his minions have mostly taken care of all the problems that the adventurer's used to take. Ainz came up with the idea to change the Adventurer's Guild main goal from being a mainly monster hunting group into real adventurers that would explore the unknown. He met with the city's guild leader to discuss about it, intriguing him with this new proposition. Ainz would make suggestions such as providing the support and training through Mare's new underground training labyrinth constructed to train new recruits.

However, he has to make his goals known to all adventurers who would come to his kingdom. In order to attract potential new recruits, he decided to head to the Baharuth Empire to spread the word and to obtain some new supplies for his newly-formed organization. Just before he left, he also sent Albedo on a mission to act as an official delegate to the Re-Estize Kingdom to start official ties between the two nations.

He asked Guild Master Ainzach to accompany him to act as both a guide and adviser, recommending Ainz to see Osk who was known as the best weapons merchant in the empire. Along the way, Ainz became interested about a dwarven sword that Osk has in his collection and was particularly curious about the rune inscriptions on it, which bore a striking similarity to his own world. When he set up the meeting, the two talked a little about each other and start official trade relationship. It was to the point, where Ainz even allows Osk to see his undead face and was one of the few humans who did not bear any ill will towards his undead appearance. They also talked about the Martial Lord of the Empire's Gladiator Arena, where Ainz wanted to participate in a battle against him. Since Osk was the current champion's main sponsor and was a fan of strong warriors, he thought it would be interesting to see the fight happen, so he set up a match between the two.

At the Arena, he met face to face with Go Gin and at that moment, the two complimented each other out of mutual respect. Before the fight begins, Ainz turned off his High tier physical damage nullification effect to fight on more equal grounds against the Martial Lord. They also made a deal that if Ainz were to win, Go Gin would become a part of his nation to help trained his new adventurers while if Go Gin were to win, he would eat him, believing he can become more powerful by doing so. After sparring with each other, Ainz finishes the warrior off by striking him with one of the stilettos charged with Fluder's magic and killed him. Afterwards, he began to revive the Martial Lord, proclaiming his intentions to the people in the arena for all to hear publicly.

He came back to E-Rantel, satisfied with his accomplishments and at the same time was confused with Emperor Jircniv's sudden declaration of wanting his empire to become his vassal state. On the other hand, Ainz was more interested in the rune-mark weapon he saw, inciting him to make plans to visit the dwarves and its nation first while leaving the details of the vassalization to Albedo and Demiruge.

The Craftsman of Dwarf Arc
Not long after he came back from his business back in the Empire, Ainz has went and visit the Dwarven Kingdom in order to try to establish official relations with them through trades. More specifically with the objective to understand the runes they crafted into their items and weather if there was a possibility that another player had something to do with them.

It was also around this time that Cocytus has send one of the lizardman to hand his report in. He took the opportunity to ask the lizardman about information on the Dwarves in which he told Ainz that he does not know much other than there was someone from their tribe who had been to their nation before. The lizardman thinks Zenberu would be the best candidate to ask any information on them for that matter regarding the dwarves. After the talk, he also contacted both Fluder and Ainzach for any more information available. Unfortunately, they happen to know very little about it, so Ainz decided he should head to the lizardman village himself to ask for the information directly.

He went to the Lizardman Village to speak with Zenburu Gugu about the Dwarf Kingdom. While at the same time, as well as to offer his blessing for Zaryusu Shasha and Crusch Lulu's new born child, presenting them a gift to the lizardman chief as a reward for his loyalty. He made arrangement in bringing Zenburu with him to readily act as a guide during his journey to the Kingdom via Azerlisia Mountain range. Also, accompanying him along the way were a few of Ainz's personal picked guards, two of his Floor Guardians being Shalltear, Aura and their respective minions.

Finding that the Dwarven Kingdom proved to be a bit of challenge, Ainz has no other choice but to use his memory-control spell to get Zenburu to remember the details of his past journey. However, not even his spell was enough to make Zeburu remember much as they still think the terrain is proven to be very effective in hiding its entrance to the Kingdom. Nevertheless, Ainz and his group ended up eventually finding it, but what they stumbled upon was just an empty city with no signs of dwarves at all.

Trivia

 * In the Web Novel, Ainz was thought to be one of the Thirteen Heroes.
 * Momonga renames himself as Ainz Ooal Gown so that guild members or players may know its existence.
 * Nigun of the Sunlight Scripture assumes Ainz's true identity happens to be one of the Evil Deities.
 * Under his adventurer persona as Momon, he holds the moniker 'Dark Hero' that refers to his black plate armor and heroic combat prowess. Evileye speculated that Momon is a Godkin, beings with the blood of Players in their veins, due to his display of power that surpasses humans.
 * The Slane Theocracy's cardinal have almost mistaken him for one of the Six Great Gods, Surshana known as the God of Death, but quickly dismiss that idea.
 * Both the villagers of Carne Village and the lizardman tribes of the Great Lake have build their own respective statue of Ainz Ooal Gown as a sign of loyalty to him.
 * Due to Ainz's illusion spell, the Swords of Darkness believed that judging from his facial appearance which is black hair and eyes visually, they see people like him are commonplace in the South.

Quotes

 * (To the Staff of Ainz Ooal Gown): "Should we get going, symbol of our guild? No, that’s not it. let us go, symbol of our guild."
 * (To Demiurge): "It is truly beautiful. These stars were meant to decorate me. I will leave my body here, in order to obtain this jewel box that belongs to no one."
 * (To the Knights): "You dare to chase little girls, but don’t have the courage to stand against enemies?" 
 * (To the Knights):"Do not cause any trouble here. If you choose to not listen to my advice, next time you and your country will burn together." 
 * (To Albedo about Humans): "Well, upon meeting the humans here, I could only muster enough empathy to treat them as insects, but after conversing with them, I’m starting to see them as small animals."
 * (To Nigun): "The deal that I mentioned before is that I hope that you would quietly surrender your lives, this way you can be spared from physical pain. Otherwise, if you resist, which would be very stupid of you would have to pay the cost of dying in despair and misery."
 * (To his Guild Members): "My friends, what do you think about me hogging this glorious name? Will you be happy? Or displeased? Tell me if you have any feedback, tell me this name isn’t mine alone. I will change back and use Momonga without hesitation."
 * (To Albedo about Shalltear): "I am the one known as the Guildmaster of Ainz Ooal Gown. When engaging in PVP, the actual chance of victory is high, invincible against even those with flawless builds. How can I lose to the type of person who solely relies on their attribute. Furthermore, the most important fact is the strong bond I have with Peroroncino. Know that this battle was over even before it had begun Shalltear."
 * (To the Unknown Enemies) “I will definitely make you deeply regret your own foolishness. Do not think you can get away so easily when you anger us, Ainz Ooal Gown.”
 * (To Himself): "I am Ainz Ooal Gown. With that name at stake, there can be no defeat."
 * (To Shalltear): "Realize now, Shalltear. You face Ainz Ooal Gown, with the combined might of all Forty-One Supreme Beings from the beginning, you had no chance of victory."
 * (To Himself): "Repaying good with good and evil with evil. This is the norm of the world."