Momonga is a regular salaryman who leads a guild in an DMMO-RPG known as Yggdrasil. After twelve years of playing the game, the servers are finally shutting down. Momonga logs in for the last time, seeing the game to its end. However, after the clock strikes midnight, nothing changes.

Grateful that they weren’t cast aside, the floor guardians experience the rule of their true master for the first time. Momonga quickly assess the situation and works toward protecting the tomb from invaders while contemplating what he must do.

Momonga continues his efforts to protect Nazarick from the unknown forces he may be up against in this world. As he manipulates the Mirror of Remote Viewing, he notices a village being attacked and decides to test his strength against humans.

Momonga finds that the attackers of Carne Village were Slane Theocracy soldiers dressed as people from the Baharuth Empire. As the attack to lure and eliminate Gazef Stronoff continues, Momonga takes this chance to continue his tests…

Momonga sets out with Narberal disguised as humans under the names of Momon and Nabe for the city of E-Rantel. There they register to become adventurers in order to gain more information about this unknown world. As they do, evil gathers around them.

While Momonga has some doubts, he accepts Nphirea Balear’s request under the condition that the members of the Swords of Darkness join them. Though her urge to kill keeps distracting her, Clementine continues to slowly find her way to Nphirea.

Momonga and his group continue to Carne Village. There they see that the villagers are working toward fortifying their defenses against possible future enemies. Nphirea meets up with Enri and asks her about this man named Ains Ooal Gown.

After Momonga registers Hamusuke with the guild, he goes to Nphirea’s home to find that his client has been kidnapped. The zombified remains of the Swords of Darkness litter the storage room. And there, Momonga finds the tortured body of Ninya.

Momonga and Narberal begin their respective battles against Clementine and Khajit. Momonga takes this chance to learn about the mechanics of fighting in this world, but in the end, he must show Clementine the consequences of offending him.

Momonga finds out that Shalltear has revolted against him, due to something that had happened while she was on her mission with Sebas and Solution. The story rewinds a bit and goes over that very event. What could possibly change her loyalty to him?

Momonga does damage control at the guild while he assesses the reason for Shalltear’s revolt. Coming to the conclusion that she is under an incurable status effect, Momonga goes to the treasury to retrieve some of the powerful weapons of Nazarick.

Though Shalltear’s skill set puts Momonga at a complete disadvantage, he steps forward into battle. He gave various world items to his guardians to ensure the safety of Nazarick in his absence. Now, all that is left is a battle of life and death!

Momonga reminds Shalltear that he is the master of Nazarick and that his name carries the weight of all the supreme beings of Ains Ooal Gown. After the battle comes to a close, Momonga quickly takes action to strengthen the defenses of Nazarick.

Officers of the Slane Theocracy gather to discuss recent losses. The noblemen of Estize plot to push back the Empire. Ains surveys a world map as his plans are set in motion. Shalltear recovers from her ordeal.

Cocytus gives a declaration of war to all the tribes of the Lizardmen, expecting an easy takeover. However, the Lizardmen decide to try to unite their tribes against their common foe.

Zenberu tests Zaryusu’s strength in combat, while the latter defends Crusch’s honor. The Lizardmen chiefs conduct a war council, and formulate a strategy to defend themselves against their common enemy.

The alliance of the Lizard men win the battle and defeat the army of undead. The defeat guardian Cocytus and the new ability to learn from their mistakes, prove that the guardians can adapt to new situations. Ainz Ooal Gown therefore changes his tactics, ordering Cocytus to bring the Lizard men to their knees and under the rule of the Great Tomb of Nazarick.

At the outpost in the Tob Forest, Ains strategizes with his guardians, and imposes Shalltear’s penance upon her. The Lizard Man chiefs assemble and receive Cocytus on the battlefield for their final showdown.

Sebas happens upon a near-lifeless woman, and takes her under his protection. Brain, left defeated by his encounter with Shalltear, meets up with Gazef. Members of the Blue Rose take measures against a drug plantation

Gazef finds Climb practicing with his sword outside the castle, and asks to spar with him. Renner and Lakyus examine the coded document recovered by Evileye. Sebas finds himself beset upon from all sides over Tuare.

Climb delivers Lakyus’ message to Evileye and Gagaran, who offer guidance to the young man. Climb happens upon some men beating up a boy in the street, who is then rescued by Sebas, from whom he seeks training.

Sebas begins his raid of the brothel from one side, while Climb and Brain enter from the other side. While Climb covers the exit alone, he is confronted by Succulent and Cocco Doll trying to flee and a desperate fight begins.

Ains calls on Sebas to answer for his actions, and to discuss what is to become of Tuare. Renner meets with the Blue Rose, then Marquis Raeven, to consult with them about her planned attacks against Eight Fingers.

Demiurge takes charge of Nazarick’s forces, laying out the mission to strike at Eight Fingers. Meanwhile, Lakyus details a similar mission to her squad captains. Sebas, Climb, and Brain raid Six Arms’ compound together.

Evileye petitions Momon to help her, and he begins fighting the disguised Demiurge. As Climb and the others try to get Tuare out of the compound, they face resistance. Renner convenes an emergency strategy meeting.

The guardsmen and adventurers face a daunting array of demons until Momon arrives and takes charge. Brain once again comes face to face with Shalltear. While Evileye is occupied, Demiurge reveals his plan to Ains.