Invasion of the Royal Castle

The Invasion of the Royal Castle is a battle that took place during the Demi-Human War 43 years before the arrival of Natsuki Subaru into the world.

This battle marked a serious change for the entire war, as the three major commanders, including the undead Libre Fermi, attempted to take the Royal Castle for themselves. However, despite their efforts, they were unable to do so. Libre was completely destroyed, Valga Cromwell was defeated and was imprisoned beneath the mansion of Miklotov McMahon, and Sphinx lost her limbs and escaped, only to be secretly captured by Leip Barielle.

Despite this battle being so major, the war did not end, and the Demi-Human Alliance continued fighting under the banner of Cragrell Dawson.

Background

Due to the mass of casualties caused by the Battle of Aihiya Swamp, a large number of warriors, both human and demi-human, were risen as corpse soldiers. Because of this and the massive loss of their army, the Kingdom's forces were forced to retreat. Though Valga and the Demi-Human Alliance kept relatively quiet over the following month, they obtained new allies from the various demi-humans who had previously remained neutral, and the Kingdom remained vigilant as they reorganized their military, with the Zergev Squadron also being rebuilt. Leip was punished and demoted to a baron, being tasked with guarding the castle, and Wilhelm was tasked with patrolling the Royal Capital, which at times led to him being forced to slay any dissenters, one of which claimed that the capital would also face destruction.

Eventually, fires and fights began popping up across the nation, and the regional lords were forced to contend with their rebellions on their own with their own forces since the army's numbers had not recovered. Although Bordeaux Zergev expected this was a part of Valga's plan, he was surprised at how underthought it was, allowing his spite to sway his thoughts. However, remembering what one of the dissenters he slayed said, as well as Valga's victories at both the Battle of Castour Field and Aihiya Swamp, Wilhelm deduced that the uprisings all over the country were just a distraction and that the capital and castle were the real targets. Trusting this judgment, Bordeaux led the Zergev Squadron to the castle to defend it. Meanwhile, Valga's company had already breached the castle, having used secret tunnels in the sewers to enter, and they killed several knights that were left to guard the castle.

Just before the Zergev Squadron reached the castle, they were stopped by the castle's knights, which included Leip, who chastised them for their actions. However, thanks to the assistance of Roswaal J. Mathers, she ordered the knights to stand down and for the Zergev Squadron to defend the castle. As such, the Zergev Squadron split up to defend the castle, and Wilhelm left Grimm with Roswaal to defend her alongside Carol Remendis. Shortly after entering the empty castle, Wilhelm realized where the enemy might strike, and he and Bordeaux split up, Wilhelm taking Roswaal's group with him.

Battle

The Battle in the Audience Chamber

Shortly after arriving in the audience chamber, Bordeaux came across the undead Libre, who succeeded in drawing the first blood. Although disappointed by not being able to fight Sphinx, being given a chance to avenge Pivot's death, he readied his halberd and clashed with Libre. Throughout the fight, Bordeaux found himself marked with wounds, and he realized that if Libre had still been alive, he would have been terrifying to fight. Still, he eventually managed to push through Libre's attacks, and he struck at Libre. However, instead of being able to finish him off, a blast from an Al Jiwald broke through the floor, and the two fell beneath.

The Battle in the Chapel

Shortly after arriving at the chapel, Wilhelm's group came across signs of battle and several headless knights, evidence that the enemy had already appeared in the castle. Opening the chapel, the group encountered Valga and Sphinx. Valga claimed to not be surprised that Wilhelm killed Libre, having not been told the truth, and Sphinx, seeing Roswaal determined that the king would not be appearing, Roswaal having already ensured that the king would be elsewhere. With Wilhelm and Valga claiming they knew how to arrive at the castle, everyone prepared to fight, with Valga using the magic circle, the bones of his ancestors, and a massive amount of mana to greatly increase the size of his body. After swinging his fist and knocking Grimm and Carol away, Sphinx left through the broken ceiling of the chapel, and Wilhelm to Roswaal to take the others and chase after her while he battled Valga.

As they fought, Wilhelm narrowly avoided Valga's strikes and found that he couldn't pierce through his skin, and eventually, Valga landed a critical hit on him. Despite this, Wilhelm emerged from the rubble and managed to slash into Valga's eye, and immediately after, damaged joints in his fingers and his lip. Despite this, Valga managed to land another hit on him. Soon after, Valga's injuries began healing. Striking Wilhelm once more, he prepared to finish him off, only for Grimm to appear and stop Valga's strike while Carol and Bordeaux attacked, breaking Valga's fingers. His life saved, the fight continued without anyone interfering.

As Wilhelm continued to dodge Valga's endless swings, he eventually managed to reach his blade that was lodged in the giant's lip, and he tore it out. After slashing his fingernails off, Wilhelm targeted Valga's chest, tearing it open and removing the bones that had increased Valga's size. With his body shrunk to normal size, Wilhelm and Valga clashed one last time, with Valga causing massive damage to the chapel and Wilhelm dealing untold damage onto Valga. With the floor of the chapel collapsing, Valga fell into the hole.

The Witch Hunt

Chasing Sphinx onto the ground floor, Roswaal managed to deftly evade her attacks, leap into the air, and bring the Witch back to the ground, where Carol and Grimm were waiting. However, taking a strike from Grimm, Sphinx was sent flying into a wider space, where she had greater room to move. As the other chased after her, she unleashed another large spell at them. However, thanks to Roswaal's magic protection cloak, she was able to cancel the spell and prevent it from harming them. In response, Carol attacked her, evading an attack while midair, and cleaving Sphinx's left arm off. Back on the ground, Sphinx was then faced with Roswaal, who struck her from below and caused her great internal damage. However, as Carol and Roswaal came to finish her, Sphinx removed her robe, revealing a magic circle, and fired Al Jiwald at her enemies, which Grimm deflected with his shield.

The blast was deflected into the ceiling, causing it to fall apart, and both Bordeaux and Libre, who were above, fell to the floor. Despite the sudden arrival and apparent reinforcement, Libre, who had regained some of his mind, cut off Sphinx's remaining arm. Immediately after, Libre's body turned to dust. With Sphinx flying away, Roswaal chased after her while the others went to assist Wilhelm. Using her steel balls, she managed to bringing Sphinx back to the ground, and she attacked with another steel ball, dealing even greater damage to Sphinx. Despite this, Sphinx managed to escape Roswaal by entering into the secret passageways beneath the castle.

Having successfully made her escape, Sphinx ran until she encountered Leip, who intended to use her in his schemes. Taking her for himself, he later encountered Roswaal, who he told that he had personally finished Sphinx off and burned her remains, passing Roswaal a ring on a string as proof. With Roswaal gone, he took Sphinx back to the Barielle Domain.

Aftermath

Due to the invasion's ultimate failure, the various uprisings across the country subsided. The Zergev Squadron were once again credited for their great achievement, and much of the cleanup was left on their shoulders. With the discovery of the passageways beneath the castle, there would need to be future studies into it and determining exactly where they lead. As for Wilhelm, he finally came to realize the meaning that he held his sword for, and eventually, he became the vice commander of the Zergev Squadron.

Without their main leaders, the Demi-Human Alliance were in shambles, leading them to rely on their last remaining leader, Cragrell Dawson. Because of this, the war did not come to an end. Valga, who survived the ordeal, was discovered by Miklotov McMahon beneath the castle, and he was imprisoned beneath the McMahon Manor, where he would remain for decades. Likewise, Leip brought Sphinx back with him, intending to use her for his own plots, which would later lead to his own demise, the undead incidents in his domain, and finally, the Great Disaster.