Subjugation of the Blight Dragon

The Subjugation of the Blight Dragon (邪龍討滅戦) was a battle that took place between 38 and 39 years before Subaru's arrival in the world, and it is the primary conflict of Sword Demon Battle Ballad.

Following an attack on the Astrea Manor and the McMahon Manor, Stride Vollachia, who had kidnapped the pregnant Theresia van Astrea and cursed Carol Remendis, led his followers to the Kingdom's Commercial City of Picoutatte, where he summoned a powerful and dangerous Blight Dragon: the black, three-headed Dragon Valgren. Chasing after his mortal enemy, accompanied by the Zergev Squadron, the Royal Army, and Roswaal J. Mathers, Wilhelm van Astrea led an assault against the man, the Witch Cult's Sin Archbishop of Pride, and intended to save his wife and bring an end to Stride's schemes.

Ultimately, despite the loss of Roswaal, all of Stride's entourage were killed, with Stride and his wife being devoured by Valgren. Valgren, manipulated by Stride's Authority of Pride following his death, went on a rampage, leading to its epic confrontation with Wilhelm. The battle finally came to an end when the Divine Dragon made its appearance to uphold the covenant to the Kingdom, annihilating Valgren and reaffirming the people's faith in the Kingdom's covenant. The events here were later immortalized in a song called the Subjugation of the Blight Dragon.

Prelude

A short time after the Demi-Human War ended, Stride Vollachia had set his eyes on the Kingdom as part of the show he wanted to create. His incursions against the Kingdom had resulted in Veltol Astrea being left disabled as well as countless other damages. His transgressions reached a boiling point when he cursed Carol Remendis and made her kill Veltol before the both of them made off with the Sword Saint, Theresia van Astrea.

Wilhelm, who'd already been trying to track Stride down, was informed of those events by Bordeaux. He found out from Tishua, who'd been made a mouthpiece by Stride using his curse rings, that Stride was awaiting them in Picoutatte. As a result, Bordeaux Zergev quickly rallied a subjugation force together which numbered approximately 1000 strong. The subjugation force consisted of soldiers and knights who revered Theresia for her role in ending almost a decade-long Civil War. The force also included the Zergev Squadron, now commanded by Wilhelm, as well as Roswaal J. Mathers. The force set out from the Royal Capital and rushed towards Picoutatte.

Battle

Prior to the arrival of the Kingdom's Subjugation Force, Stride made his preparations by getting Melinda to find people with Divine Protections to be sacrificed for the purpose of summoning the Black Dragon. As well as that, he instated his Magic Circles around the city so that the area there would be cut off from the world, meaning that Divine Protections would stop working there, as well as disabling the "magical alert syste" set up by the Divine Dragon, which would notify him in case of an attack. Meanwhile, Melinda helped set up the defenses by using her Evil Eyes to control all the citizens of Picoutatte, turning them into a swarm to be launched against the Kingdom's Forces. Finally, Stride ordered Carol to kill the sacrifices with his Dragon Fang, and completed the process of summoning the Black Dragon Valgren.

As the Kingdom's Subjugation Force approached the gates of Picoutatte, they were met by a head on volley of flame from Valgren's breath. This devastating pre-emptive blow caused serious damage to their forces, killing many and injuring many more. Despite that, the Kingdom's Forces managed to rally their strengths again and pressed on into the city after sending their injured back to nearby towns.

The rallied forces pressed into the city, and were met by the effects of the Magic Circles Stride had implanted. As a result, they dismounted from their Dragon Carriages and continued on foot. However, they were soon met by the swarm of citizens, Melinda was controlling with her Evil Eyes. Their offensive battle quickly turned to a defensive one so that they weren't crushed in the stampede. The Kingdom's Forces tried to defend themselves against the swarm without killing any of the citizens, however reinforcements soon arrived from Stride's faction in the form of one of the Twin Shura. Raizo quickly cut his way through the Kingdom's defensive formation, attacking the trapped Knights from behind, threatening to collapse their line. His challenge was quickly met by Wilhelm, and then Roswaal, however, Vollachia's strongest warrior quickly came to bolster the Stride faction's defenses. In the confusion, Raizo was able to use his ability to transport Grimm Fauzen and Roswaal to the Spire rooftop where Stride was waiting at with Valgren above.

Battle on the Streets of Picoutatte

Back on the streets of Picoutatte, the weakening Royal Forces continued to hold their defensive line against the controlled citizens whilst Wilhelm fought Kurgan and Bordeaux fought Raizo. The tide of battle started to turn when Bordeaux, though sustaining heavy injuries, defeated Raizo. Wilhelm, in turn, managed to defeat Kurgan, leaving him mortally wounded as the citizens of Picoutatte began to come back to their senses thanks to Melinda's Evil Eye being defeated by Theresia.

Battle on the Spire Rooftop

Taking place simultaneously with the battle in Picoutatte, Roswaal fought against the other Twin Shura whilst the cursed Carol was forced to fight against her lover, Grimm. Contrary to expectations, Grimm was able to hold his ground, so Stride commanded Shasuke to kill Carol. However, he was thwarted by Roswaal who sacrificed herself for her friend. The tide of battle changed after this, with Grimm causing Stride to summon his Yang Sword Vollachia, which ultimately led to him being forced to cut his own left arm off, losing half of his curse rings and as a result, control on Carol and Valgren. The ensuing fight led to both his, Melinda and Shasuke's death.

The Subjugation of Valgren

In death, Stride's curse tools continued to bind Valgren to his will, and made it unleash its fiery breath down at the streets of the prematurely celebrating Royal Forces. Heavy losses were incurred amongst the Subjugation Force and the Picoutatte citizens. Wilhelm and Grimm challenged the Dragon, and were successfully able to wound it. However, the tide of battle shifted completely in their favour when Gionis Lugunica stirred, having been able to use the help of Valga Cromwell to destroy the Magic Circles that prevented him from calling for Volcanica's assistance. As a result, Volcanica appeared and destroyed Valgren and healed the world around them of their wounds and the dragonfire.

Aftermath

The battle was a major victory for the Lugunican military, despite incurring heavy losses among their forces and the non-combatants of the city. Volcanica's appearance reaffirmed Lugunica's might thanks to the covenant binding them, reaffirming itself as a deterrence to any enemy invaders.

Furthermore, the victory allowed them to seize the political upper-hand with their negotiations for compensation and culpability with the Vollachia Empire, extraditing their political prisoner Kurgan back to the Empire in the hope of trying to get them to acknowledge Stride's existence. However, Stride was effectively erased from history by Vollachia, and according to Vincent Vollachia, who later discovered his journal, anyone who learned of him could have been punished for it.