When Momonga had enough of sitting idly by as YGGDRASIL is about to be permanently shut down for good, he makes the final decision to celebrate the end of the game in style. Reasonably so, he heads towards the surface teleporting through various rooms by using the Ring of Ainz Ooal Gown. He flies off to a small little island in the Grenbera Swamp and sets up 5000 fireworks to explode and burst into the sky. While blinded by the brilliant flash of light, Suzuki notices that his surroundings have changed from a swamp to a ruined city.
Unable to determine his situation and exact location, Suzuki decides to patiently explore his new surrounding. To gather information stealthily, he turns himself invisible. At the same time, he also activated his passive ability to detect any Undead nearby. As a result, he could sense the presence of an undead close to his surrounding, causing him to hide momentarily before deciding to seek the target out. Suzuki notices that the ruins are not made of reinforced concrete and believes he is somewhere in YGGDRASIL but determines it to not be the case as some of his spells behave differently unlike those from the game.
Using 'Distant Vision,' he sees it to be a mere zombie putting his mind at ease. He later detects another presence of an undead, this time heading away from him. Determined not to lose another source of information, Suzuki tracks his newfound target. After catching up to the target, he realizes it to be just a little girl who is alone. He politely greets her and introduces himself as Suzuki Satoru. He asks where her parents are to which the girl responds by stating that they are gone, indicates she is an orphan. The girl later introduces herself as Keno Fasris Invern.
Unsure what kind of person Keno was, Suzuki still deemed her a necessary source of information. He introduces himself using his real name Suzuki Satoru. Sensing that something was amiss, given this girl was all alone in a city full of zombies, Suzuki asks if they could relocate to a safer location. However seeing that she did not fully trust him, he offers to wait. Keno then timidly guided him to the underground sewers where she made her home.
Though shabby, Suzuki takes note of the collection of books and scrolls in the room. After amazing Keno with his display of magic, summoning chairs and a lamp. He then asks her to explain what happened to the city to the best of your ability. He expressly states that he have no intention of making this a one-sided interaction, willing show you a proof of his own sincerity. He offers an exchange of equal value with her, as he knows very little about the situation, and intends to pay her with magic items or hard currency instead.
Keno glares at him in hostility, but to Suzuki's surprise begins her tale. Keno was the princess and the only daughter of King Invern and Queen Annie Fasris Invern of the nation of Inveria. During training with her mother, they had been mediating to strengthen her magical abilities when a sheering pain erupted from her body. She was not alone as her mother, maid and father experience the same agony. Her parents attempted to use teleportation magic to get Keno to safety only to realize that there was interference. Fight through the pain Keno blinks out of consciousness but not before her mind made contact with 'something'. By the time Keno awoke, she saw that her parents had been transformed into zombies. Not only that she felt there were physiological changes to her, her cold skin and crimson eyes.
In addition, whatever had caused her parent's undead condition, affected the entire city's populace. Keno chooses to stay and wait for help as she could not simply abandon her family and leave. In addition, she believed that she would be easy prey for whatever monsters existed out beyond the city. She held on to a faint thread of hope that the other cities would come to investigate, given that it was the royal capital. However, no help came, as two years passed Keno began to suspect that this strange undead conversion phenomenon had spread to the nearby cities and even affected the entire country. Time became blurred to Keno that even her sense of time was confused. It would seem Keno had lived by herself all, looking for a way to restore everyone to their original selves.
Suzuki hearing her story now understood Keno's solemnity in contrast to her youthful age due to the amount of time that had passed for her as an undead. Seeing that it was rude to speak to her like a child Suzuki corrected himself and speak to Keno as a junior. For the reason why she was now living in the sewers, Keno had done her research at the royal castle however the princess had felt a powerful undead being appeared outside the city, one that was more powerful than herself or even her parents. And when it had entered the city, Keno who had no faith whatsoever in her ability to triumph in battle, she took everything she could carry and ran from the castle to the sewers.
Keno then kneels to the ground and begs Suzuki to undo the fate that had befallen her city and loved ones. Confused on her pittance, Suzuki clarifies that he was not the one responsible for the city's fall. He gives her a short account of how he spontaneously appeared in Inveria, resolving the confusion. Suzuki moved by her serenity decides to aid her in defeating the undead who may have caused the undead status of the nation. Though chances that killing the undead would not restore the inhabitants to their normal selves was slim, the two decide to risk it.
The undead had now taken residence in the castle and was guarded by several of its undead servants. Given Keno's description, Suzuki believed it to be an Overlord like him and decided to take extra precautions. Using a zombie dog he guided it to the lair of the supposed Overlord. After locating the undead magic caster, Suzuki immediately teleported in the vicinity and used his magic to kill it instantly.
Seeing how relatively easy it had been to slay the undead, Keno and Susuki investigate the belongings and discover that the undead was researching the undead phenomenon that transpired. Keno did not lose hope and believed that the national treasures of the kingdom, Lost White, could restore at least her parents to their human forms. Under the advice of Suzuki, they used a test subject only for the magic to have no effect. That having failed, Suzuki tried to use his Shooting Star to divine a way to undo the undead curse but that too failed.
Suzuki consoled her to no let go of how citing that the world was big and possibly there was a way to return her people to normal out there. Sounding logical and wishing to see the world, Keno agreed to go with Suzuki on a quest. The two then set off in a wagon pulled by a Golem Horse to seek answers.
The story then takes three years later, from the viewpoint from a member of an Elder Lich group known as Corpus of the Abyss. After a year the members began to realize that they were being hunted down by an unknown entity. The liches were helpless to confront the threat as it was deemed impossible that anyone could threaten them, but as more and more of them vanished they began to feel genuine fear. One member of the organization, Kunivela finds himself under attack, at his very castle. He attempts to escape via magic but finds himself taken captive by none other than Suzuki and Keno. The pair having acquired knowledge about Corpus from the undead in Inveria had been hunting the magic casters and stealing their research in hopes of finding a method to reverse whatever be-felled Keno's homeland. Using mind control, Suzuki learns all he needs to know and kills the lich.
After two years, the two have become well traveled in the New World, exploring new sights and locations. However five years since leaving Inveria, Suzuki notices that Keno had quietly accepted that she may never cure her loved ones and become human again. Unwilling to give up, nor give her false hope Suzuki guides them back to the direction of Inveria. Arriving in a city located near Inveria, the two discover that the surrounding nations had been affected by some sort of event that turned every living thing into zombies. Without the knowledge of Keno, Suzuki meets with the leader of a group mercenaries he hired to investigate the cities affected by the undead epidemic. Using their report and the information he gathered, Suzuki tracks the epicenter of the epidemic to Mount Keitenias.
Back on the road, the pair journey to the mountain and pass through the Aina Miscegenation League, stopping at Seruk No.3 where they find the city devoid of activity. Here Suzuki parts from Keno intending to face the source of Keno's and the lands woes. Before leaving Suzuki acknowledges Keno as a member of Ainz Ooa Gown bequeathing her a Ring of Ainz Ooal Gown.
While approaching slowly and silently to Mount Keitenias, Satoru cast several buffs on himself along the way in preparation for an inevitable fight with the culprit behind this undead accident. Once he reached the main source of the enemy's lair, Satoru learned that the person who is responsible for that phenomenon happens to be Elder Coffin Dragon Lord. During the first round with this said Dragon Lord, Satoru lets Cure Elim dominate this fight against him intentionally, hoping to gather as much information as possible from it before he retreats. Once that task is through, Satoru decided to use the [Greater Teleportation] spell to escape Cure Elim's clutches, arriving back at Seruk-3’s main gate, which he had memorized ahead of time so he could teleport to it. Since he manage to learn enough about Cure Elim's capabilities, Satoru became to prepare himself with anti-divination defensive spells in case the opposition spy on him of where he currently is at the moment. Satoru changed out his gear by adjusting his equipment loadout, selecting gear and items that was especially effective against the undead or Dragons. Not only that, but he set up several trump cards in place to use and equip such as the Staff of Ainz Ooal Gown before beginning his next battle. At the same time, he equipped his World Item in order to acquire complete immunity from the Dragon Lord's Wild Magic. When Satoru finally finish his preparation work at long last, he followed his previous route back into the mountains to confront Cure Elim once again, planning to vanquish him once and for all. During the second but last match with Cure Elim, Satoru held the advantage throughout the field of battle between the two. It was to the point in which he has successfully manage to end the Dragon Lord's life without getting the chance to use all of his trump cards prepped beforehand.
Suzuki and Keno return to Inveria, only to find that even with the death of Cure, the curse upon the nation's inhabitants still remains. Suzuki insistently believes an solution is out there in the New World. Keno hearing him agrees, though she secretly harbors doubts and comes to acceptance that she may never restore her parents. The two go on an adventure once again.
Two hundred years later, Keno and Suzuki have befriended other heteromorphic beings and expanded the membership of New Ainz Ooal Gown a guild dedicated to exploring the wonders of the New World. After successfully delving into the Dolor Desert, Keno reports to Suzuki about a nest of demons that appeared in the western regions.