Soul Spores.
This was the terrifying talent behind Muzan's Soul Ability - a power that had manifested early in his development, but had taken decades to truly master. Where Doma stripped the souls from living beings and bent them to his will by force, Muzan had discovered something far more insidious.
He could integrate his soul directly into individual cells, transforming them on a spiritual level until they became extensions of his own being. These enhanced cells carried the same devastating potential as any blood demon art - capable of assimilating, transforming, corrupting, and devouring any substance they encountered. Even a single cell, empowered by its soul energy, possessed the ability to reproduce at an exponential rate, triggering explosive fission within moments.
The implications were staggering. With enough soul power, Muzan could transform an entire room into his personal domain, where every surface, every molecule of air, every grain of dust would be occupied and altered by soul spores in cellular form.
The trap had been set long before Doma and the others ever entered the Castle of Infinity. Muzan had seeded his blood beneath the floating platforms, and within that blood lurked his remaining cells - microscopic agents awaiting his command. A single thought could trigger a cellular explosion and fission, transforming solid stone into writhing flesh and blood tissue that could then form bones, organs, or any biological structure he desired.
Snap.
The grotesque tumor that had swallowed Doma writhed violently, its surface pulsing with digestive contractions as if it were chewing and breaking down the prey it had consumed. The closed, bloody mouth continued to spew acidic liquid from its corners, steam rising where the corrosive substance ate through the platform below.
But in an instant, white frost spread over the organic mass like crystalline death, transforming the lump of flesh into a glistening ice sculpture. The temperature plummeted as Doma's power asserted itself from within.
With a thunderous explosion of power, the frozen tumor shattered completely, revealing Doma covered in sticky slime, but very much alive. His colorful eyes gleamed with that familiar amusement, as if being temporarily devoured had been nothing more than a minor inconvenience.
Muzan watched motionless from his elevated position, his scarlet pupils narrowing to calculating slits. He had expected this outcome, of course - Doma would not succumb to such an easy opening gambit.
The moment Doma freed himself, countless floating platforms began to approach from all directions, their stone surfaces rippling and transforming into various forms of deformed flesh. The architectural elements of Infinity Castle became weapons as Muzan's soul spores claimed everything within range.
A platform positioned directly above Doma's head morphed into a massive eyeball, its iris contracting as it focused on him with predatory intensity. The organ tracked every subtle movement, recording every breath and micro-expression for analysis.
The flesh-and-blood platforms positioned in front and behind Doma erupted simultaneously, unleashing dense volleys of bone spears that swept toward their targets like a deadly rain. The projectiles whistled through the air with enough force to pierce stone, each guided by Muzan's will.
Several other platforms revealed giant mouths that opened wide, spewing clouds of crimson mist into the air. This wasn't ordinary blood - the vapor contained concentrated toxins, and floating in the mist were countless "disease" cells transformed from Muzan's soul spores.
If even the smallest amount of this contaminated air touched Doma's skin or entered his lungs, the results would be catastrophic. The enhanced cells would immediately begin to multiply, spreading throughout his body like a spiritual cancer until they consumed him from within.
Doma's response was as swift as it was elegant.
As he waved his ornate iron fan, wind and snow intertwined in a complex dance of destruction, thick ice crystals and razor-sharp blades of frozen air expanding outward with him at the epicenter. The power of his Blood Demon Art froze everything in the immediate vicinity, encasing the airborne threats in shells of solid ice.
But his attack didn't completely neutralize Muzan's assault. Even as the supernatural cold washed over them, several of the flesh-and-blood constructs managed to survive by rapidly growing layers of dense white bone on their surfaces - organic armor that resisted the freezing temperatures while shattering the ice blades that struck them.
"Your Blood Demon Art comes from my blood," Muzan said with cold satisfaction, his voice carrying clearly over the transformed battlefield.
The words hit Doma like a physical blow. He stared at his opponent in genuine shock, his mind reeling from the implications. The technique he had just unleashed - the same power that had annihilated the entire Twelve Demon Moons in a single devastating strike - had barely scratched the Demon King's defenses.
In that moment of stunned realization, a black shadow materialized beside him.
Muzan appeared out of thin air, but this wasn't the Demon King's true body. It was merely a cluster of cells that had split at an incredible speed, instantly forming a flesh-and-blood duplicate with all the deadly abilities of the original.
"You dare betray me?" the clone hissed, raising his hand like a blade and driving it directly into the back of Doma's skull. "Did you really think I couldn't hurt you?"
The blow landed with brutal precision. Doma's eyes widened as blood spurted from his mouth, his pupils losing focus as the devastating injury sent shockwaves through his nervous system. For a moment, he seemed genuinely surprised that the battle could end so quickly.
The gap between his power and Muzan's was far greater than he had imagined.
Soul spores operating at the cellular level were invisible to the naked eye, and this was the true horror of Muzan's evolved abilities. He had integrated countless cells into the very air itself, seeding the atmosphere with microscopic agents of destruction. Within this space, within this domain he had claimed, his clones could manifest anywhere at any time and transform into any conceivable biological weapon.
If he wished, every single cell could become an independent clone, capable of independent action. The only limitations were the finite range of his mind power and the mental strain of controlling so many simultaneous manifestations. In addition, cells separated from his main body would eventually become inactive without constant mental reinforcement - but even these limitations left him with overwhelming tactical advantages.
Without these weaknesses, neither Doma nor Kokushibo would have posed a threat.
Doma's abdomen began to swell grotesquely, his limbs twisting into unnatural shapes as the contamination spread. He had inhaled Muzan's cells during the chaotic battle, and now those microscopic invaders were growing inside his body, threatening to tear him apart from the inside out.
The previous attacks had all been elaborate deceptions. While Doma had focused on the obvious threats, Muzan's true attack had been on the molecular level.
Muzan's fury burned cold and relentless. Even if Kokushibo harbored treasonous thoughts, he would never have acted on them without Doma's instigation. More importantly, this ice demon was responsible for Akaza's death-a crime that demanded personal retribution.
Doma possessed the ability to transform his body using the Blood Demon Arts, just as he had done when he was attacked by the Upper Rank Three earlier. But Muzan knew his former subordinate too well. Before Doma could even begin to activate his defensive techniques, the Demon King's soul had already locked onto his true form and struck preemptively.
Beyond this tactical advantage, Muzan's soul pressure remained significantly stronger than Doma's. Under the crushing weight of those mental fluctuations, the ice demon found his reaction time severely compromised.
Muzan had no intention of giving him any breathing room. His determination to execute the traitor was absolute and unwavering.
"It's not bad... being killed by you, Lord Muzan," Doma managed to say, his voice distorted by the cellular transformation wreaking havoc on his vocal cords. He laughed in that stuttering, broken way, completely unafraid of death - if anything, he seemed to take a perverse pleasure in his predicament.
But his gaze remained fixed on the elevated platform where Oboro watched in silent judgment.
"It's just that... before I die, I have one last task to complete."
Those words sent an icy fear through Muzan's veins. Every instinct screamed danger as the demon king realized what was about to happen.
The countless souls dwelling within Doma's spiritual consciousness - the "little demons" he had devoured and enslaved over the centuries - suddenly acted through the cellular link with Muzan's clone. Their combined spiritual assault struck like a psychic sledgehammer.
Muzan's skull felt like it was splitting, his vision going black as the coordinated attack overwhelmed his defenses. Blood gushed from his seven orifices as his nervous system struggled to process the supernatural damage.
Doma's soul ability had never been a simple "peeling" as others believed.
The agony was indescribable. Muzan's cold, controlled expression twisted into something feral and bestial, his eyes completely bloodshot as the mental backlash severed his connection to the myriad cells he had been controlling. The interruption gave Doma the opening he needed - instead of exploding from cellular corruption, he managed to digest and neutralize the invading organisms.
At the same time, he held his breath and stopped his respiratory functions completely, preventing further contamination.
"Master Muzan," Doma said, lifting his head to smile at the writhing Demon King above him, "it seems your soul ability... can't really kill me after all."
Bang!
Rage consumed Muzan completely. His clone lashed out with bestial fury, ripping Doma's head from his shoulders in a spray of blood and bone fragments.
But what was scattered across the platform wasn't flesh and blood - it was a cluster of pristine ice crystals.
Immediately, snow began to fall throughout Infinity Fortress, the temperature dropping so quickly that respiration became visible. A white storm rolled across dimensional space, turning the demonic stronghold into a frozen wasteland.
The supernatural storm converged on the platform where Muzan stood, coalescing into a towering figure that reached nearly ten meters into the air.
Blood Demon Art: Water Lily Bodhisattva.
The massive construct bore Doma's serene features carved from living ice, its expression radiating the same angry calm that had always characterized the Ice Demon. Pure white lotuses bloomed around Muzan's position, their petals formed from compressed snow and spiritual energy.
Atop each lotus sat a female figure - Snow Princesses with their torsos exposed, half of their forms condensed from ice and snow, while the other half seemed carved from the compressed winter air itself.
All of the Snow Princesses opened their mouths simultaneously, releasing streams of freezing mist and crystalline clouds that sought to envelop everything in their path.
The Evolved Bodhisattva stretched out his massive arms, reaching for Muzan in a gesture that might have been a loving embrace - were it not for the killing intent radiating from every ice crystal in his construction.
The real battle was about to begin.