HxH: I Will Be Supreme

Oboro had acquired the ability to travel through space—a gift his soul had acquired through the wish system's rules during his time in the Dark Continent—through the wish system's rules. It was a power he'd always possessed, yet he rarely dared to use it.

The special nature of his soul made frequent spatial travel dangerous. One wrong step into the torrents of time and space, and he might never find his way back to any reality. However, with the Demon Slayer world's will offering him a degree of protection, jumping within a single dimension posed an acceptable risk.

Still, Oboro tried to avoid activating it unless absolutely necessary. He had been busy in this world for so long, and there were still countless resources left to collect. Caution had kept him alive across multiple dimensions—why abandon it now?

After familiarizing himself with Muzan's soul signature and marking it with his own energy, the demon king truly had nowhere left to hide. Every heartbeat, every terrified breath, every desperate thought—all of it resonated through the spiritual connection Oboro had forged.

"Don't be afraid," Oboro said softly as he stepped over the temple's threshold. His voice carried the weight of absolute certainty: "It's not your time to die yet."

But Muzan's expression made it clear that he didn't believe a word of it.

The evolved demon king was forced to draw upon his strength, knowing he was hopelessly outmatched. In a single, horrifying instant, the ground beneath his feet, the temple's ancient wooden structure, and every material surface transformed into writhing flesh-and-blood entities.

Several fleshy walls tore open with wet, organic sounds, and short, deformed creatures shambled through the gaps. These abominations bore human shapes, but their limbs and organs were grotesquely misplaced—like temporary failures crafted by an amateur god.

"Incredible..." Oboro's eyes lit up with genuine fascination as he observed the display.

Facing the imminent threat of death, Muzan had achieved another breakthrough. This method of creating new life involved dividing his soul as if splitting cells, then transforming the fragments into countless clones under his direct control.

Each monstrosity clutched bone weapons formed from their own twisted flesh. Blood creates people and flesh creates bones—the soul prompting cellular transformation. Since Muzan's soul cultivation was basic, he could only reshape cells into bone and flesh structures he understood best.

But what possibilities might the future hold?

Currently, Blood Demon Arts relies entirely on physical flesh. In time, they might transcend those limitations and become soul-based abilities, breaking free from bodily constraints. New power systems could emerge from soul cultivation, such as mental abilities and various supernatural powers. Cells could serve as mediums, transforming their properties into elemental attributes.

Given the historical background of the Demon Slayer world, techniques involving arrays and artifacts with embedded abilities could also be developed.

"Go to hell!" Muzan screamed, finally losing all composure.

A horde of monsters surged forward, attacking Oboro with desperate fury. Simultaneously, the entrance behind him transformed into writhing flesh and blood, sealing shut to block any retreat.

The room plunged into absolute darkness.

Several massive hands erupted from the walls, seizing Muzan and dragging him into the flesh to hide within its depths. Even now, when he had seemingly mustered the courage for a final stand, his subconscious instincts screamed at him to run.

Ding!

A crystalline note rang through the air—not in physical reality, but in the realm of souls. Muzan heard it with perfect clarity and recognized it as the unique melody of spiritual energy.

The moment the sound reached him, Muzan and his monsters froze as if someone had pressed pause on reality itself.

Oboro had finally released his soul pressure.

Muzan felt his essence stripped bare and cast adrift in a vast, merciless ocean. He could sense Oboro examining every thought in his mind through direct soul contact, reading his memories and fears like pages in an open book.

Before this man, he had no secrets whatsoever. No capital for resistance. He could only be washed and battered by those terrifying spiritual waves, knowing that the slightest hint of defiance would cause the abyss to swallow him whole.

"Get out of the way."

A single thought flashed through Oboro's consciousness.

The deformed monsters surrounding him—previously controlled by Muzan's will—suddenly shifted their allegiance and retreated in perfect unison, as if they had found a new master.

"You allocated portions of your weak soul to Doma and Kokushibo," Oboro explained conversationally as he approached the paralyzed demon king. "Sooner or later, they'll become familiar with soul power and discover the key. Like you, they'll open that door themselves, then pass this knowledge to others."

He paused, studying Muzan with clinical interest. "Soul power will spread throughout this land. For those two, the ultimate goal will be to overthrow you. They understand perfectly well that as long as you're alive, there will always be trouble."

"Your fate is connected to theirs, but it's also in your hands." Oboro knelt down beside Muzan, whose back had fused completely with the wall. "Whether you can survive depends entirely on you."

"Hurry up. Use the soul as a seed and build your own following before they catch up with you. Otherwise, when that day comes, your life will end."

Oboro raised one hand and touched the center of Muzan's forehead with deceptive gentleness.

"I'll take the core of your blood. Of course, as a reward... I'll let you see the 'beautiful scenery' you've always dreamed of."

His fingertip cut through Muzan's skin like a blade, causing bright red blood to flow from the wound. Though it didn't seem like much, the energy contained in those few drops far exceeded what Muzan had shared with his Upper Moons.

Muzan desperately wanted to resist, but his body and soul no longer obeyed him. Oboro's soul pressure forced him to surrender complete control.

The demon king watched helplessly as Oboro absorbed the essence through his fingertips.

Then, beneath the shadows, the old man's frail appearance began to transform. His white hair regained its lustrous black color, his wrinkles smoothed away, and his stooped posture straightened with renewed vitality.

Unlike Tanjiro's dramatic future transformation, Oboro's change proceeded smoothly and without fanfare. This level of power was too elementary for someone of his capabilities.

As the aura surrounding him shifted, Muzan's heart trembled with recognition. The figure before him had evolved to achieve the very goal he'd pursued for over a thousand years:

Immortal flesh and blood. Freedom from death. No longer afraid of the sun.

Despite Oboro's overwhelming soul power, such a transformation should have been impossible. The key was the Blue Red Spider Lily, and Oboro clearly knew its whereabouts. He had already claimed it.

In fact, when Oboro first appeared in the Infinity Castle, Muzan noticed traces of his cells in the old man's body. The transformation had been planned from the beginning.

Within mere seconds, Oboro returned to his prime. He rose gracefully and walked toward the entrance; the flesh-and-blood walls parted before him without resistance.

As he stepped outside, Oboro glanced back at Muzan, who remained seated in the dimly lit room. "If you're the one who survives instead of them in the end, then I can fulfill your wish. Consider it a reward for your efforts."

Beyond the temple, flat, open terrain bathed in the approaching dawn stretched out before him.

Muzan watched Oboro's retreating figure as the first golden rays of sunlight crested the distant horizon and fell directly upon the transformed man.

Seeing this scene, Muzan was struck speechless.

This was exactly what he had longed for throughout his cursed existence—the ability to walk freely under the sun without fear of death.

"What do you... want?" Muzan muttered to himself.

He truly wasn't going to die. Not yet, at least.

Everyone—himself, the Demon Slayer Corps, and every living being in this world—was being manipulated by Oboro like pieces on a game board. Muzan could feel the intentional nature of Oboro's words driving him forward in a predetermined direction.

The stage had been set for his final battle with Kokushibo, Doma, and the inheritors. He couldn't refuse. He had no right to refuse.

Considering everything Oboro had accomplished over the years, it was clear that he had planned every detail from the beginning.

But what was the ultimate purpose behind it all? Was he simply toying with everyone for his own amusement?

"Outsider..." Muzan spoke with growing certainty. "There's another dimension he's not familiar with, and another kind of creature entirely."

Despite being the ancestor of demons, Muzan was also a well-versed scholar. He didn't know where Oboro had come from, but the man's presence proved that other dimensions existed—realms beyond Muzan's reach for reasons he couldn't fathom.

The world he knew was not everything. Not even close.

And somehow, terrifyingly, that realization filled him with both dread and the faintest spark of hope.