HxH: I Will Be Supreme

Time crawled forward like a wounded beast, each day bleeding into the next with agonizing slowness. Yet somehow, in what felt like both an eternity and a heartbeat, several years had slipped past like shadows at dusk.

Oboro had long since returned to his residence, but the familiar walls offered him little comfort for what he had set in motion. The cards he'd claimed from the three Upper Rank demons, Gyokko, Doma, and Kokushibo, had become instruments of calculated chaos. Over these blood-soaked years, he had transformed dozens of demons, each one carrying the same burning conviction to change this rotting world and save it from itself.

But these weren't Muzan's mindless puppets. The beliefs Oboro instilled in them burned with a different fire entirely. His demons moved with purpose, targeting the corrupt shogunate officials who held the real world in a stranglehold. Every assassination and calculated strike was designed to shake the foundations of power and plunge the nation deeper into the chaos it needed.

Yet Oboro was far too cunning to let his creations easily achieve their goals. After all, willpower required tempering, like steel heated and hammered until it became unbreakable.

As one of the shogunate's high-ranking officials, Oboro played his role to perfection, secretly orchestrating every move from the shadows. Sometimes he would drop hints to the Demon Slayer Corps; at other times, he would do the same with Muzan's faction. This ensured that obstacles would rise to challenge his demon inheritors at every turn. It was the ultimate puppet show, with Oboro pulling strings that stretched across battlefields and boardrooms alike.

The Demon Slayer Corps hunted his successors out of duty, but Muzan's interference stemmed from a more dangerous place: curiosity. The demon king could no longer approach Oboro directly, but his hunger to understand how these demons had broken free from his blood's control drove him to desperate measures. He needed specimens to study and answers to questions that gnawed at his ancient pride.

What emerged was a three-way war that painted the countryside crimson. Among Oboro's inheritors, some fell, their wills tested and found wanting. Others survived, growing stronger with each trial. The most interesting development came from those who realized the bitter truth: alone, they were merely drops in an ocean of corruption. Their vision required companions and armies, the kind of power that could only come from unity.

Several of his transformed demons had begun forming their own factions, some openly declaring themselves leaders of growing rebellions. The seeds of revolution took root in soil watered with blood.

During these years of orchestrated carnage, everyone had been forced to evolve or die. The swordsmen of the Demon Slayer Corps, the demons under Muzan's command, and even the civilians caught between them had grown stronger under a pressure that would have crushed the previous generation. Only those who could survive this chaos would earn the right to participate in what was to come.

In this regard, Oboro's purpose had been perfectly achieved.

He remembered observing the breathing techniques of Pillars Rengoku and Giyue years ago. During their battle with Gyokko, they could barely enhance their physical attributes through controlled breathing. Now? The current generation of Pillars could strengthen specific limbs at will and had begun tempering their internal organs through advanced breath circulation techniques.

Thanks to several swordsmen now stationed within the shogunate itself, Oboro's knowledge of the Demon Slayer Corps had grown extensive. The world was no longer ignorant about demons and demon slayers. Even common samurai had begun training specifically to combat supernatural threats, adapting techniques passed down through whispered legends.

These changes rippled outward like stones thrown into still water.

Of course, as the man behind the curtain, certain aspects of the "power system" required his careful guidance. Through carefully worded correspondence, he helped the Ubuyashiki clan preserve the core strength of the Demon Slayer Corps while ensuring the shogunate wouldn't interfere with their operations. Without his subtle manipulations, the Ubuyashiki clan would never have managed to keep their organization intact on their own.

After everything that had transpired, he was certain that young Ubuyashiki Kagaya had become much more convinced of his own convictions. Sometimes the greatest lessons came wrapped in the cruelest packages.

The tragedy of these years defied description. Countless civilians had perished, their screams echoing through villages turned into graveyards. Of all the Pillars Oboro had once known, only Giyue and Rengoku remained standing among the Demon Slayer Corps. Muzan's forces had suffered devastating losses. The reputation of the Twelve Demon Moons hung by threads. The Lower Ranks were replaced so frequently that their names became meaningless. Even the Upper Ranks had fallen in battle.

Oboro's next moves crystallized in his mind with perfect clarity. First, although the Demon Slayer Corps had evaded government control, the knowledge and techniques of demon hunting must be disseminated among the general population. Only when the soil was vast enough would the seeds be numerous enough to eventually produce quality that could change everything.

The greater the hostility that his demons faced, the more Muzan and his followers would be forced to evolve beyond their current limitations. Pressure creates diamonds, after all.

Second, the shogunate could not be allowed to completely crumble. Even in chaos, everything had to remain controllable. If the current government fell and new leadership emerged, it would bring his inheritors closer to achieving their goal of "saving the world." Oboro couldn't allow them to have such easy victories.

He had given them hope with one hand. With the other, he arranged their despair.

As he had learned long ago, will burns brightest when surrounded by the deepest darkness.

The Demon Slayer Corps continued to evolve and grow stronger with each trial. His demon inheritors were evolving, too. Some had developed the ability to transform humans into demons independently of Muzan's control, though their numbers remained limited. Abilities that had once belonged to Oboro alone were spreading to his most exceptional successors.

The only faction that seemed stagnant was Muzan and his original demons. However, even that wasn't entirely accurate. Surviving on such high-pressure battlefields and experiencing countless life-or-death encounters was its own form of evolution, providing hard-won experience and growth.

This generation's combat prowess already exceeded that of any previous generation. Oboro found himself genuinely curious about how powerful future generations might become under such intense selective pressure.

Several months later, Oboro sat at the entrance of his mansion and watched a group of children chase each other through the streets with wooden swords. Their voices rang out with declarations that they would become demon slayers when they grew up.

In the past, outsiders rarely ventured near his residence. Ordinary civilians instinctively avoided getting too close to seats of power. However, his return coincided with an influx of refugees and displaced families seeking shelter in the city. Most of these children were from elsewhere, and their youth shielded them from the fear that paralyzed their elders.

They only knew that every day, a man in a black haori sat by the compound's gate, offering them sweets and occasionally teaching them basic swordwork with wooden practice blades. As word spread, more and more children began gathering around him.

"Teacher," a snot-nosed boy approached with wide, curious eyes. "Have you ever killed a demon?"

"Mm." Oboro nodded with gentle acknowledgment.

"Are demons scary?" the boy asked, his voice barely above a whisper.

"If demons are scary," Oboro replied with a warm smile, "wouldn't that make me scarier for killing them?"

The boy's eyes lit up with excitement rather than fear. Oboro ruffled his hair affectionately before sending him back to play with the others.

Then, his attention shifted to the street corner where a familiar figure approached with measured steps.

Years hadn't changed the man's appearance much, but his eyes told a different story. From the moment he appeared, his undisguised intensity focused on Oboro like a blade seeking its target.

As he drew closer, he glanced at the children playing before fixing Oboro with a steady gaze. "It's hard to imagine someone like you exists."

His voice carried the weight of accumulated pain and determination. "All the suffering they're experiencing now, you caused it. And yet, here you are, the architect of their misery, sitting peacefully like a benevolent elder and teaching them skills as if you aren't planning to destroy everything they know."

"Did Ubuyashiki Kagaya tell you all this?" Oboro's smile remained unchanged, though something sharper flickered in his eyes.

If members of the Ubuyashiki clan and certain individuals within the Demon Slayer Corps still couldn't grasp his true intentions at this point, then perhaps their usefulness had run its course.

"Why come to me instead of hunting Muzan?" Oboro asked, his tone almost playful.

"He rarely shows himself anymore. He hides deeper than anyone else. Probably afraid of you," the man replied without hesitation.

Muzan had indeed abandoned his identity as a daimyo, retreating into deeper shadows than those he commanded. With his paranoia and shapeshifting abilities, as long as he avoided direct confrontation, even the Demon Slayer Corps would struggle to corner him.

"Go back," Oboro said in an almost paternal tone. "You've finally awakened the Demon Slayer Marks and reached this level through breathing techniques. Yes, your lifespan will be shortened, but you won't die young if you're careful. There's no need to throw your life away here."

"Going back would just be wasting time," the man replied firmly. "I've reached my limit with my current abilities. I can't afford to wait any longer."

He paused, his gaze never wavering. "Besides, with Muzan's current level of caution, finding and fighting him is nearly impossible."

"I thought you were smarter than this." Oboro sighed deeply as he rose to his feet.

"Some things still need to be done," the man said with absolute conviction.

Giyue stared directly at Oboro. When he spoke, his words cut through the air like thunder. "You are wrong."

Four simple words that denied everything Oboro represented and everything he had built and orchestrated.

"Let's go, then." Oboro turned and began walking away from the children and their innocent games.

Today, the Water Pillar had come for revenge. This was Giyu, the successor of the Thunder Pillar, Sakonji Urokodaki, from years past. Though they shared breathing techniques, the naming conventions for Pillars had evolved. Jigoro Kuwajima, another Thunder Breathing user, had once held the title of Sound Pillar, too. (A/N: This is some weird shit that I can't explain.)

Oboro had always harbored respect for Otomo Giyue. The Pillars of that generation, including Giyue, taught him valuable lessons about the true power of inherited will and unbreakable determination.

However, Giyue hadn't come solely for revenge. His greater purpose was to eliminate a threat to the Demon Slayer Corps and the world itself. In this moment, what he represented was purely personal conviction, completely separate from any organizational mandate.

The fact that he had come at all meant that he had already settled his affairs and made peace with his choices. Oboro suspected that even the Demon Slayer Corps leadership, including Ubuyashiki Kagaya himself, was unaware that one of their Pillars was here, preparing to face the architect of their greatest trials.

The sun began its descent toward the horizon, painting the sky with shades of blood and gold. In the distance, children's laughter echoed through the streets. They were blissfully unaware that two forces capable of reshaping their world were about to collide in a battle that would determine far more than their individual fates.