Fall of the Re-Estize Kingdom was a war between the Re-Estize Kingdom and the Sorcerer Kingdom that resulted in the dissolution of the former as an independent state. The Argland Council State and Adventurer's Guild also joined the conflict on the side of the Kingdom.
The war itself was triggered by the badly thought out actions by a single foolish nobleman of the Re-Estize Kingdom's New Faction. This was an attempt to increase the grain prices that the Sorcerer Kingdom had deflated due to their mass-produced high-quality grain imported to the Re-Estize Kingdom in order to turn a profit for his domain. His plan was to rob the Sorcerer Kingdom's Grain Transports in order to acquire it for himself, and cause a shortage of the product. At the same time, deflate the grain prices to make a profit from his own inferior stock and make even more profit by selling the stolen grains as his own product.
In other words, this incredibly foolish plot was hatched by the Nobleman in question together with the assistance of two other Barons. They all did this believing that, even if a war of retribution should break out between their nation and the Sorcerer Kingdom, the enemy nation does not possess the necessary numbers to invade the Kingdom. Even if they did only the territories and domains in the Kingdom's borders would be taken, far away from their own territories. Thus, the two felt safe enough to help their "leader" in his scheme and provide additional back-up for their "leaders" forces who would simply stand back in the sidelines just "in case" he would need assistance as he did the actual deed in order to prevent themselves from being identified or connected to him should the plot backfire.
Due to the lack of loyalty from the grain transport's guards, who opted to peacefully leave rather than fight off the thieves, the nobleman and his serfs managed to easily acquire the grains for himself. More-ever because of his lack of foresight or insight, the nobleman in question didn't even bother hiding his involvement to the incident. Even going so far as to arrogantly/foolishly flaunt the Sorcerer Kingdom's flag as a "War Prize" based on his successful "Battle of Conquest" against the Sorcerer Kingdom, believing that it would garner him support and praise back at the Royal Capital and not bother hiding his actions at all.
Caught completely off guard by this unexpected occurrence, the Sorcerer Kingdom had initially thought that this incident was the doing of another unknown third party who had manipulated or mind controlled the noble in question in order to initiate a complex plot. Hence, they immediately began preparing countermeasures to this "new enemy" before the Sorcerer King accurately figured out that it was in fact nothing more than the Nobleman in question's own stupidity and vanity getting the better of him. Due to their prior plans of conquering the kingdom anyway using more peaceful methods now being ruined because of that nobleman's actions, the Sorcerer Kingdom thus then decided to further expand their initial plans further and take full advantage of the situation in order to make an example of the Re-Estize Kingdom as well as conquer it. This was done so in order to send a message to all other nations not to antagonize them or underestimate the Sorcerer Kingdom as the Re-Estize Kingdom so foolishly had. Due to realizing the probable increase in foreign interaction or even covert operations against the Sorcerer Kingdom by other Nations.
The Sorcerer Kingdom decided to attack earlier than announced. Elder Liches attacked one city, while frost dragons airdropped multiple undead on another. Mare was responsible for taking countless lives with his nature magic and reducing much of the kingdom to rubble. Demiurge used a network of shadow demons to prevent the capital from finding out about these attacks until it was too late. Many nobles including Marquis Raeven were coerced into switching sides by Albedo for the sake of their families and the inhabitants of their territories.
The site of the northern campaign of the Sorcerer Kingdom against the Re-Estize Kingdom. The Sorcerer King sought to cut the Kingdom from allying with or leaving a path to the Argland Council State. The city of E-Naüru was defended by a coalition of adventurers led by Four Armaments. In the end, the battle ended in the Kingdom's victory after Azuth Aindra defeated the undead commanders of the army. This unexpected victory gave hope to the Kingdom's citizens that they could successfully repel the Sorcerer Kingdom's invasion with the help of such powerful individuals in their ranks. However this battle, in truth, would be the only tactical victory of the Kingdom in the entire conflict.
Despite King Ramposa III insistence that there could still be a peaceful resolve with the Sorcerer Kingdom, His son and his retainers believed that a peaceful resolution had long since passed due to the Sorcerer Kingdom's acts of immense savagery in their invasion and them making their intent to completely annihilate the Re-Estize Kingdom overwhelmingly clear. To prepare their country for war, the Crown Prince led a quiet coup against his father to take command of the nation for its survival.
The Slane Theocracy, having long since desired to have the Kingdom destroyed due to its failure as a nation (its incredibly lax governance and immense corruption) secretly agreed to the Sorcerer Kingdom's declaration of war. Fully aware of the absolute impossibility of the Kingdom winning the war, they instead chose to offer aid of helping their fellow humans from that nation. For that reason, the Theocracy took full advantage of the one sided war of annihilation to strengthen their own nation as a whole. This was done so by ordering their most powerful Scripture the Black Scripture to enter into the Kingdom's lands in order to recruit and convince the Kingdom's most powerful and talented adventurers into migrating and fleeing to the Slane Theocracy. It was considered to be an operation that ended with an immense gain to the Theocracy's military due having successfully convinced a gigantic bulk of the adventurer's to escape with them upon realizing the hopelessness of the Kingdom's situation. The only failure in the operation was the fact that the Kingdom's two Adamantite adventurer groups; Blue Roses and Red Drop did not accept their offer and instead antagonize the Theocracy's representatives.
Newly crowned King Zanac attempted to try at least one last time to sue for peace with the Sorcerer King. Going alone to meet them before their forces battled, he personally met with Ainz Ooal Gown. While he failed to convince the undead to call off his army, he did appeal to Ainz's human side and successfully made the enemy monarch rethink his course of action and possibly made him think of accepting their surrender instead. Knowing that he had failed, Zanac returned to his camp to meet his end with dignity on the battlefield. However several minor nobles desperate to survive, plotted, and ambushed Zanac and his guards. Taking his head, they presented it to Ainz to become his vassals. Though they intended to appease the Sorcerer King with their "offering," their actions only ultimately fueled his motivations to burn what he saw was a corrupt nation to the ground in retaliation for King Zanac's death due to deeming that there was no longer anyone else worth saving within the corrupted nation and personally had the traitorous nobles tortured viciously together with their families for their betrayal of their own king.
Disgusted by the nobles' betrayal and the assassination of Zanac and deeming that there was no longer anything worth sparing within the corrupt kingdom, Ainz turned the conquest of the Kingdom into a large-scale massacre to completely wipe away the eye-sore of a nation from the face of the earth. The Royal Army are the first to feel his wrath and they are wiped out in an hour.
Eight Fingers managed to bring a least a thousand people who were loyal to them to a newly constructed village to save them from the Sorcerer King's wrath; they also free Ampetif Cocco Doll so he can be of use to the Sorcerer Kingdom.
At the start of the invasion of Re-Estize, the armies of the Sorcerer Kingdom marched to destroy the city. They were briefly attacked by an interloper who was none other than Azuth Aindra. The adventurer goaded Albedo to pursue him, knowing full well that he had no chance of victory. The main purpose of his attack was to draw the Sorcerer King's protection so that his ally Tsaindorcus Vaision could assassinate the former.
Tsaindorcus confronted the Sorcerer King. Their battle was intense and deadly but it came to an end once reinforcements arrived to aid Ainz and Tsaindorcus fled before he was overwhelmed. Despite failing to kill Ainz, Tsaindorcus was confident that he can defeat Ainz the next time they met after learning his full capabilities. Unbeknownst to the Dragon Lord, the "Ainz Ooal Gown" he has faced was actually Pandora's Actor in disguise.
Lakyus Alvein Dale Aindra intended to remain in the capital and defend it to the bitter end. However, the same could not be said by her fellow comrades of Blue Roses. To escape the Kingdom's destruction, the group incapacitated and mind controlled their leader to force her to flee the city with them.
With all hope for the Kingdom gone following Tsaindorcus' failure, the Sorcerer Kingdom attacks the Royal Capital. The Kingdom's last remaining elite warriors, Brain Unglaus and Vesture Kloff Di Laufen, attempted to make a last stand. However, in the end, the capital fell with little resistance.
Third Princess Renner finally reveals her treason to the Kingdom by assassinating her own father, King Ramposa III. At the same time, the Sorcerer Kingdom besieges the Royal Palace and takes it in no time at all. Afterward, the former princess is welcomed to Nazarick as an honorary member.
With no-one else left, Princess Renner's bodyguard, Climb, is forced to face off against Sorcerer King Ainz Ooal Gown by himself. Unbeknownst to him, though, his "heroic last stand" was merely a set-up designed to allow his mistress to maintain her good standing in front of him post-defection.
To repay Philip, the man who in his vanity led to such a wasteful campaign of retaliation upon the Kingdom and to eliminate all loose ends of her previous acquaintanceship with the idiotic noble, Albedo personally invaded his domain to finally eliminate her failed pawn. Wanting to make his death as agonizing as possible, Albedo single-handedly invaded his domain and successfully impaled every single one of the domain's inhabitants from the nobles, their families, servants and villagers in front of Philip's mansion as a surprise. The only one to remain alive was Philip who after being shown the gruesome sight of his slaughtered family, friends and servants, was promised a slow death under extreme torture by the Prime Minister's hands. Albedo done so after being requested by Philip's father to make his son pay for his foolishness and satiate her hatred for him ruining her master's initial plans for the Re-Estize Kingdom.
The Re-Estize Kingdom was left in ruins with only a small handful of survivors who managed to stay alive either by escaping before its downfall or submitting to the rule of the Sorcerer King. The only monument left of the Kingdom was Ro Lente Castle which was left untouched whilst the entire royal capital was turned into a literal mountain of rubble and set ablaze by Guren to serve as a reminder to all of the consequences of going against the Sorcerer King and his kingdom.
The Fall of the Re-Estize Kingdom also caused the Sorcerer Kingdom's neighboring kingdoms to prepare themselves for what they believe to be an "inevitable" war with the Sorcerer Kingdom, as seen where Platinum Dragon Lord of the Argland Council State had attempted to assassinate the Sorcerer King and the Slane Theocracy had acquired additional manpower by assimilating some of the strongest and most talented Adventurers from the doomed Re-Estize Kingdom for their own military. Further hinting to their future diplomatic relationship with the Sorcerer Kingdom.
On the other hand, the Sorcerer Kingdom also gained the extra benefits of being able to successfully train the Floor Guardians of the Great Tomb of Nazarick in war, strategy, conquest, and preparing massive/large scale invasions they can use as references for future wars and battles for the Sorcerer Kingdom. As seen where several of the Floor Guardians successfully conducted several experiments via trial and error to create various unique invasion strategies using their current resources. As seen where Shalltear Bloodfallen, who had successfully created a highly effective invasion strategy that takes full advantage of her transport network of using their conquered Frost Dragons to air carry their Soul Eaters to bombard and annihilate entire cities and towns. Meanwhile, Mare Bello Fiore successfully gained experience on how to destroy large scale cities, residential areas and places of dwelling using his magic cleanly and effectively to massacre all of its inhabitants in mass. And both Demiurge and Albedo successfully obtained further political, espionage, and wide scale information manipulation experience for future operations. As for Cocytus, he obtained first hand experience on how to launch and lead a large scale invasion force.
Additionally the Sorcerer Kingdom had also obtained its first credible information on the Natural Magics present in the new world thanks to the interloper Riku Agnia's assassination attempt on their Monarch, who made excessive use of Wild Magic during his duel against "Ainz Ooal Gown" and additionally the higher ops of the Sorcerer Kingdom also obtained information on the Adamntite Adventurer of Red Drop, Azuth Aindra due to his battle against Albedo and him making excessive use of his Armor of Reinforcement. In addition to obtaining the solid information on Wild Magic, the Sorcerer Kingdom had also successfully given the interlopers a false estimate of the "Sorcerer King's" power level and overall abilities that effectively rendered them overconfident as a future advantage in Riku's future assassination attempts.
Now that their fallen enemies' former territory was now the Sorcerer Kingdom's for the taking, they have done so with extreme swiftness. Renner is transformed into a demon and joined the ranks of Nazarick and manipulated Climb to do the same after his resurrection; adding the tactical genius and leadership skills of the former third princess to Nazarick's collection of valuable assets. Nazarick also claimed many useful items during their onslaught such as the legendary magic sword Razor Edge and the recently re-acquired prototype of Armageddon Evil.