Battle of Aihiya Swamp

The Battle of Aihiya Swamp (アイヒア湿地帯攻防戦) was a major battle during the Demi-Human War that took place 43 years before the arrival of Natsuki Subaru. The battle is known for being the largest and deadliest engagement of the war, with casualties disproportionally being of the human side.

Initially starting as a wider counter-insurgency effort launched by the Royal Army, the campaign quickly centered around Aihiya Swamp, where the resistance by demi-humans was heaviest and the leaders of the rebellion were rumored to be operating from.^[1] However, unaware to the Kingdom's forces, this was actually another trap set by the Demi-Human Alliance's strategist, Valga Cromwell, who managed to use the Kingdom's wariness of magic circles to fuel another one and lead them into a situation they hoped to avoid.

This battle resulted in a massive number of the Royal Army's forces being completely annihilated, including the majority of the Zergev Squadron, including their vice commander, Pivot Arnancy. Further rebellion was consequently incited across the country, and because of the army's reduced numbers, each revolt was left to be taken care of by the lords in charge of each respective region.^[2] Likewise, this also left the Royal Capital extremely vulnerable to attack.

Background

Following the Battle of Redonas Plateau came the Battle of Castour Field, in which the Royal Army found themselves routed by Valga's strategies, and many of the Kingdom's forces were lost due to the expansive magic circles that were placed prior to the fight. Because the Kingdom sorely lacked the necessary knowledge to properly process the threat of the magic circles, they brought in a specialist, Roswaal J. Mathers, to study the circles. During the first investigation, they encountered the Witch Sphinx, who commanded undead forces composed of the deceased warriors of both sides who fell on the battlefield. After quelling this small force, the Lugunican government was made aware of the threat at hand, and they began an organized effort of studying the properties and effects of magic circles and ways to counter them, with the simplest solution being to physically destroy them. Meanwhile, Valga and Sphinx continued strategizing and experimenting with the information they collected from the prior battles.

As the war continued, Roswaal continued to join battles with the Zergev Squadron in order to counter any magical traps. Eventually, the battle was deemed the heaviest in Aihiya Swamp, where the leaders of the Demi-Human Alliance were rumored to be. With the Kingdom unaware of their strategies, Valga and Sphinx prepared a magic circle that would activate after other prior set magic circles were destroyed, which would successfully turn the Kingdom's wariness against them. With the government still wary after their first massive failure in Castour Field, they determined that the demi-humans would eventually have to reach their limit. Ultimately, they decided to send the military to Aihiya Swamp.

Despite this, the original commander of the forces met his end after being struck by a stray arrow in a previous battle. As a result, command of the forces was given to Leip Barielle, who had achieved previous victories during the war. Soon, the Zergev Squadron was also called forward, and alongside Roswaal, they made their way south.

Battle

Roswaal's Investigation

Soon after arriving at Aihiya Swamp, the army was split into four smaller armies. Three of them moved forward in the battle while the fourth, led by Razak Gildark, who was brought back to the frontlines despite having been previously responsible for teaching new recruits and other knights, was to sit in the back and keep their eyes focused beyond the border, anxious of the potential movement of the Vollachia Empire's forces due to the fighting's proximity to the border.

Concurrently, specialists of the human side were scrambled to target magic circles, as doctrine dictated. Leip, familiar with the order of battle, was keen to notice the apparent lack of adaptation towards the Royal Army's countermeasures and found it suspicious. After chastising a general for his lack of forethought, he sought Roswaal's advice. Claiming that the placement seemed strange, she asked for permission to look into a certain part of the battlefield, where she thought there might be something critical. With Leip assigning ten soldiers to protect her and Carol Remendis, they left to investigate.

Coming across a magic circle at the spot she went to investigate, just as she was examining the diagram, it activated, responding to the destruction of all of the other magic circles in the swamp.^[3] All of the humans affected found themselves brought to their knees under the immense weight and pressure of the circle's effect, as if they were standing in a large amount of a syrupy liquid and feeling as though they were suffocating. Though Roswaal could very well have decoded the circle, Sphinx appeared to prevent that, killing six of the soldiers with her while threatening Roswaal to join her. Despite this, Roswaal refused, and the two entered battle, Roswaal able to resist the circle's effects.

With Roswaal equipping her gauntlets, she managed to quickly overwhelm Sphinx, forcing her to just barely fly upward before her life could be claimed. Believing that Roswaal had a counter to knock her out of the sky, Sphinx retreated. Meanwhile, Roswaal made quick work of the magic circle with her yellow eye, freeing everyone from its effects.

March of the Zergev Squadron

In a little over six hours since the start of the campaign, the furious hammer of the Royal vanguard had already smashed through the entire front, obliterating any and all Alliance resistance, and never allowing their opponents the chance to form proper battle lines. Among the fighters, the Zergev Squadron met little resistance, with Wilhelm Trias, Grimm Fauzen, Bordeaux Zergev, and Pivot Arnancy deciding to continue forward into the center of the fighting to rip out the roots of the enemy forces, choosing not to report to Leip, as they expected him to treat them like tools and pawns.

As the fighting progressed, Libre Fermi arrived on the battlefield, intending to challenge Wilhelm to a duel on the field, having seen his immense skill and deeming him too powerful for the others to handle. Shortly after the clash began, Libre's speed and unique weapon proved to be too much for Wilhelm to handle. Although not taking damage from their exchange, neither could he land a hit on Libre. However, even when Libre's speed increased, Wilhelm seemed to be having fun, laughing even as he took a strike from Libre. Although he countered and took Libre's hand, he was sent flying by another strike from Libre, who was entirely unaffected by the loss of his hand. With Wilhelm being cornered, the other core members of the squadron surrounded Libre to cut off his escape and join the fight. Despite this, Libre, whose hand quickly regenerated, decided to step back so that the next phase of the battle could start.

The Tides Turn

All across the swamp, a very literal change in the air began to be felt by the humans. The air becoming denser, the smell of iron from blood and the steel of weapons replaced by the moist scent of swamp water. People began to struggle to move and felt as though they were suffocating, as if being trapped beneath water. With the true magic circle taking effect in response to every other magic circle being destroyed, all of the Royal Army's soldiers found themselves at the mercy of their enemies, who were entirely unaffected by the circle.

Despite not wanting to point his blade at enemies who cannot fight back, Libre point his blade at Bordeaux, claiming that slaying the Zergev Squadron would break humanity's hopes and make them speak with demi-humans to settle for peace. Despite this, Wilhelm managed to make himself move, and he stopped Libre's blade from reaching Bordeaux, much to Libre's shock. Still, Libre overwhelmed Wilhelm, and just as he was about to kill him, Pivot managed to move his body, and he jumped in the way of Libre's strike, yelling at everyone not to let Wilhelm die.

Roused by his cry, the remaining members of the Zergev Squadron followed suit, fighting against the effects of the magic circle and jumping to protect Wilhelm's life by fighting off Libre. However, each member of the squad was killed by Libre, one by one, until there were only a few survivors. Even Grimm had stood in to protect Wilhelm, using his shield to defend him and lasting far longer than their squadmates. But even still, Libre managed to slash Grimm's throat, incapacitating him as well. In a rage, Wilhelm pounced Libre before he could finish off Grimm, and the two fell down a hole, beating at each other as they fell.

At the bottom of the hole, free from both the fall and the effects of the circle, Wilhelm, enraged by the slaughter, took up his sword and challenged Libre. Despite having previously been able to overwhelm Wilhelm, Libre found that Wilhelm's skills were sharpening, and he was struggling against the Sword Demon. Eventually, Wilhelm managed to strike at an opening, breaking through his blade and piercing through Libre's neck. Though, this failed to kill him, and Libre prepared himself to kill Wilhelm. However, before he could do so, he was pierced by a bright ray of light fired by Sphinx. Surviving the shot, Libre turned his blade on Sphinx, but he was quickly dispatched. Deciding to leave Wilhelm alive for observation, Sphinx turned Libre into a corpse soldier and took him with her.

The Rise of the Corpse Soldiers

Meanwhile, as Pivot's life came to an end in Bordeaux's arms, the dead, including Pivot, began to rise once more. As the undead Pivot throttled Bordeaux, Grimm, barely conscious, knocked him off of his commander, and with Pivot setting his sights on Grimm, Bordeaux cut him down. Being forced to face the dead members of his squadron, Bordeaux cursed Sphinx as he cut them down. Across the battlefield, undead forces continued to rise, and ultimately, the Royal Army was forced to completely retreat.

Aftermath

The casualties for the Royal Army were estimated at greater than 60%,^[4] with every single soldier involved suffering some kind of effect from the magic circle. Meanwhile, the army commanded by Razak was left relatively unscathed. From the overall standpoint of the Royal Army, they lost a grand total of 40% of all of their forces.^[5] and sacrificed nearly twice as many men than in the battle of Castour Field, making it the greatest loss of life since the start of the war.^[6] Likewise, the Zergev Squadron of formerly eighty men was now down to eleven.^[7] Meanwhile, despite Libre's death, the Demi-Human Alliance was ultimately unfazed, as they were left unaware that Sphinx had turned him into a corpse soldier.

Due to the losses incurred, Leip was blamed for the loss at Aihiya Swamp, and he essentially became a war criminal, even being accused of having slain other people, including former commander Crumere. There were likewise other officers who took on similar blame and became scapegoats. Afterward, the military once more went through restructuring. With most of the Kingdom's army now dead or fighting as corpses alongside demi-humans, Lugunica could no longer afford to fight the demi-humans as a unified force, every battle fought from then on would be one taken to them, the Lugunicans always on the defensive. In the absence of a true standing army, local commanders took it upon themselves to defend their own territories, a losing battle in the long run.^[8]

The reinvigorated Alliance, bolstered by undead numbers and the swelling of previously neutral demi-humans now finding a cause to fight for with victory in sight, began a nationwide mass uprising, escalating a regional conflict into an all-out war of annihilation, as wished by Valga Cromwell. Ready to avenge his fallen brethren, he decided that it was about time that the horrors of war strike the heart of the Kingdom of Lugunica: the Royal Capital.^[9]

References