As Yoriichi entered the Infinity Castle, the oppressive, eerie silence was broken only by the dull sound of his feet hitting the wooden platforms that stretched endlessly around him. The walls warped and shifted with each step, as if the entire castle were alive, drawing him deeper into a twisted, unnatural labyrinth.
Two demons waited, poised to strike the moment he appeared. The first, with a body warped by mouths and eyes, lunged with blinding speed. Gyokko's limbs stretched grotesquely, each one reaching out like serpentine tendrils to ensnare him in their grasp.
But Yoriichi's blade was already in motion, moving so quickly it left trails of blinding sunlight in its wake. With one fluid motion, he severed the demon's arms, each strike precise, leaving Gyokko writhing in pain. The demon's body convulsed, his mouth gaping open in a silent scream, his eyes reflecting nothing but disbelief as he realized his attempt was utterly useless. As Yoriichi's feet touched down, gravity shifted, bending to the castle's twisted nature, but he remained steady, his stance unharmed.
Surrounded by shifting walls and endless corridors, Yoriichi found himself in the heart of the castle's deadly design. He took in the strange architecture around him, noticing the castle's dimensional distortion, likely crafted by a Blood Demon Art of unfathomable strength. Yet, as complex as it was deadly, the architecture only steeled his resolve to end the Demon King.
The castle, both intricate and lethal, appeared woven together by the will of a powerful demon. Such twisted power needed to be stopped; this unnatural creation was a testament to Muzan's authority in this place.
Without hesitation, he sprang off the wooden platform to the next ones, each movement calculated and precise, evading obstacles as he closed in on the demon he had partially dismembered. Yoriichi's blade glinted under the warm light of the place, an otherworldly glow as he raced forward.
The demon, sensing his monstrously accelerating approach, screeched in horror, but before it could react, Yoriichi's red blade met its neck in one clean, decisive cut. The head fell silently, and the demon's eyes, filled with shock, raged as it realized its circumstances. It was an almost tranquil ending, robbed of noise by Yoriichi's unmatched speed.
However, the peace was shattered when the body convulsed instead of crumbling away, thick veins pulsing grotesquely. The demon's voice, now a shrill, deranged cry, filled the space as it writhed.
"Where is your Master?" Yoriichi's voice cut through the demon's nonsensical shrieks, unshakable and unwavering, though he expected no coherent reply.
"MUZAN-SAMA! MUZAN-SAMA! THAT MAN—YOU WILL DIE!" the creature howled, its voice laced with mania. Frenzied growths began to bulge across its body, the hideous transformation reshaping it in an attempt to regenerate and retaliate. The name "Hantengu" slipped from its twisted mouth, mingling with senseless cries, like a warning call sent out to alert its kin.
Yoriichi's gaze fell on the second demon, a twisted, elderly figure cowering in fear just behind the corner of a warped wooden wall. The demon muttered feverishly, insisting it had done nothing to deserve such a fate, words that only fueled Yoriichi's resolve.
The Demon Slayer was not one to waste time on such lies; his hand gripped the hilt of his blade, his eyes never leaving the trembling figure. Without a word, he leaped forward, his Nichirin blade slicing through the air with deadly precision. In a single, fluid motion, the demon's head separated from its body.
As Yoriichi's blade completed its arc, something unusual happened. From the severed body, many monstrous figures burst forth, each one manifesting a different form of the demon he killed. Rage, sorrow, joy, and anger. They burst forth from the remnants of the fallen demon, filling the space with piercing shrieks and mocking laughter as they prepared their Blood Demon Arts. Each demon advanced from the remains, snarling and preparing their Blood Demon Art to unleash upon him.
Sun Breathing: Forth Form—Burning Bones, Summer Sun.
His strike flowed seamlessly from one form to the next, each cut moving faster than the demons could react. As the demonic clones lunged at him with their fearsome attacks, Yoriichi's blade deflected each blow with unparalleled accuracy.
The demon embodying Joy, Sekido, roared with fury, lightning sparking across his spear-like weapon as he thrust it forward. Yoriichi's eyes narrowed. Sun Breathing: Third Form—Raging Sun cut through the air, a blinding arc of sunlight meeting the electric charge head-on and neutralizing it. The clash sent shockwaves through the room, but Yoriichi's strike was relentless, ending Sekido's life before the demon could even register his defeat.
Another demon, Karaku, leaped at Yoriichi from above, manipulating powerful gusts of wind through his Blood Demon Art. His claws sliced through the air, creating a tornado meant to tear Yoriichi apart.
The Demon Slayer met the assault with Sun Breathing: Second Form—Clear Blue Sky, spinning his blade in a perfect circle, dispelling the whirlwind, and carving through Karaku's midsection The demon's eyes widened, the surprise frozen on his face as he crumbled to the floor. His body was cut in half just as his head rolled.
Aizetsu attacked from behind, his spear aiming for a vital point, but Yoriichi anticipated the strike. His blade flashed in a downward arc, the heat scorching Aizetsu's weapon and reducing the demon to ash. Urogi, the final embodiment of Hantengu's fear, leaped from above, wings spread wide, a deafening shriek filling the air. Yoriichi's grip tightened on his blade, and with one powerful sweep, he unleashed a blinding flare that silenced the screech, vaporizing the demon in a burst of flames.
The final form of Hantengu, Urogi, launched himself at Yoriichi, wings outstretched and talons gleaming as he dove with terrifying speed. His mouth opened wide, unleashing a piercing scream intended to disorient his opponent. Yoriichi's ears rang as he took a calming breath, raising his blade and focusing his concentration entirely on the enemy before him.
A warm, blinding slash was unleashed from his sword, dispelled Urogi's screams, and sliced through him in an ethereal burst. The demon's body disintegrated in the radiant glow, leaving no trace of his existence. Flames coated everything around Yoriichi.
Every one of Hantengu's split forms was obliterated by Yoriichi. The battle ended faster than it was started. Much to anyone who would see, Yorichii's breathing remained steady, his stance unshaken. The Castle Overseer trembled upon seeing this as it released the true strength of that particular demon slayer.
As silence fell over the castle, Yoriichi's gaze shifted to the trembling form of Gyokko. The demon's visage was twisted with a primal fear as he recoiled, his instincts screaming at him to flee. Yet, he was paralyzed under Yoriichi's cold, steady gaze. Memories of Muzan-sama's past flooded his mind, filling him with dread. He realized that if the higher-ranked demons could not stand against this man, neither could he.
Gyokko's mind raced, struggling to comprehend why he felt an overpowering fear he had never known before. What was it about this human that made him feel as though his death was inevitable?
Even though he had been summoned urgently to the Infinity Castle to deal with this intruder, the full extent of the situation had been lost on him. He had barely comprehended the true danger that appeared in the castle until now.
Just moments ago, he had watched, stunned, as another Upper Moon—someone stronger than himself by rank—was annihilated without hesitation by this man. If a demon of higher rank had met such a swift end, what hope did he have?
The creeping dread festered within him, stirring a bitter hatred toward the Demon Slayer. But even that resentment was cut short, for as soon as Gyokko attempted to summon his fish demons, they were effortlessly reduced to shreds.
The demon's armored flesh, so formidable against lesser opponents, was effortlessly pierced by the red glow of Yoriichi's Nichirin blade. In a single, final stroke, Yoriichi severed Gyokko's head, sending it plummeting into the endless void below.
...
Two imposing figures materialized not far from Yoriichi with a biwa sound that made the atmosphere feel dense and crackling with malice. One of them, a demon with slick, golden hair and dazzling, rainbow-colored eyes, took a moment to absorb the carnage around them. He had a funny look on his face as if the entire situation provided him great amusement. The second demon had a steely-blue skin tone and an aura of hostility that seemed almost visible in the air.
"Oh, Akaza-san, what are we to do now?" the striking demon spoke, eyes sparkling with twisted glee. "Gyokko and Hantengu have been dealt with so swiftly! It seems this Demon Slayer is no ordinary pest! Quite chilling, don't you think? Ah, I'm shivering! My whole body is getting goosebumps! Perhaps we should team up and fight him together, hmm? Let's make a good team!"
"Shut up." Akaza's jaw tightened, and a vein bulged visibly on his forehead as he shot a lethal glare at his companion. The demon was already annoyed with Douma's relentless chatter, his tolerance wearing thin. He would have struck the smug smile right off Douma's face if Muzan's orders hadn't been absolute. His master's command was paramount, restraining him even in the face of such infuriating company.
Akaza's attention turned back to the Demon Slayer before them. He was used to sensing his opponents' fighting spirit, a powerful-willed presence that fueled his desire for good combat. But the man before him was an enigma. The human's aura was as silent as a night as if he were simply... not there.
The complete lack of fighting spirit unsettled Akaza further, filling him with a frustration he could scarcely contain.
As Yoriichi took a single, resolute step forward, his Nichirin blade erupted in flames, casting a fierce glow across the chamber and throwing both Akaza and Douma into stark relief. The lack of fear in his gaze was a defiance unlike anything Akaza had encountered; it seemed to unnerve him, a feeling compounded by the sheer speed with which Yoriichi closed the distance.
In a mere heartbeat, Yoriichi was upon them.
Destructive Death: Compass Needle.
Akaza reacted instinctively, fists igniting with his aura pulsing in rhythmic waves as he readied himself for impact. But Yoriichi's movements were seamless, his Sun Techniques weaving effortlessly around Akaza's blows. With each motion, his sword left trails of sunlit flames that seared through the air, pushing Akaza onto the defensive. Each clash of Yoriichi's blade against Akaza's fists sent out shockwaves, yet Yoriichi's movements were so fluid that Akaza barely had time to counter.
From the side, Douma's amused chuckle broke through the sound of battle. His Blood Demon Art swirled around him as he conjured a barrage of lethal ice shards, sending them whistling toward Yoriichi. But as the shards closed in, Yoriichi rotated, unleashing a blazing swing in a sweeping arc that incinerated the ice before it could touch him. The sheer power emanating from Yoriichi's blade melted through Douma's attack instantly, leaving the Upper Moon demon momentarily stunned.
"Upper Moons?" Yoriichi's voice was quiet yet carried a weight that made both demons tense. He advanced with lethal intent, his blade a blur as he lunged toward Akaza.
Defeated by a weak human!?
Destructive Death: Annihilation Type!
Akaza, driven by a mix of fury and desperation, unleashed destructive attacks, thrusting his fists forward in a powerful strike aimed at obliterating Yoriichi. But the Demon Slayer countered effortlessly, his swordwork so precise that he deflected and parried every move Akaza made.
In a flash, Yoriichi sidestepped, bringing his blade down in a swift, arcing slice that forced Akaza to retreat, barely avoiding his own death by inches.
Blood Demon Art: Cold White Princesses.
Douma, now fully serious, smirked and summoned massive ice sculptures that thrust at Yoriichi with chilling intent. Yoriichi's eyes locked on them as the Sun Breathing filled his body with warmth despite the creeping coldness, his blade cutting through the icy figures with blinding speed, the strikes from his blade vaporizing them into the mist.
Douma's smug expression faltered as he watched his ice disintegrate before it could even touch the Demon Slayer.
Refusing to yield, Douma called forth an even larger ice construct, this time merging it with his own demonic aura to strengthen its resilience. But Yoriichi remained unfazed. In an instant, he was upon Douma, his blade glowing with a powerful flaming hue.
Sun Breathing: Seventh Form—Beneficent Radiance.
The attack was so swift that Douma barely registered it before his ice construct shattered, the impact sending him sprawling backward, wounds opening across his body from the sheer force of the strike.
Breathing heavily despite their infinite stamina, Akaza and Douma regrouped, the once confidence was now shaken as they faced the unstoppable force. The Demon Slayer, calm and undeterred, prepared for the next strike, his blade gleaming with sunfire that promised their imminent destruction.
Douma, attempting to buy them time, conjured a wave of glistening ice with his Frozen Lotus Blood Demon Art, filling the chamber with a blinding chill as he launched shards of ice toward Yoriichi. But the moment they neared, Yoriichi used Sun Breathing: Second Form—Clear Blue Sky, spinning in a deadly arc that deflected the ice shards and sent Douma staggering back, his eyes wide with anger.
Yoriichi's assault continued as he closed the distance between himself and the two demons. His sword blazed with the intensity of a sun, its threat palpable even to demons. He swung upward with a force that sent Douma reeling. The slice burned through Douma's defenses, searing his flesh and leaving deep, smoldering gashes in its wake that failed to regenerate properly.
Desperate, Akaza roared and attempted a full-force strike with Destructive Death: Annihilation Type, his fists surging with raw power as he aimed for Yoriichi's chest. Yet, in the blink of an eye, Yoriichi brought down his blade horizontally. His strikes blurred into a flurry of sunlit arcs, each swing precise and devastating to the demon's life. Akaza's fists met nothing but burning steel, each strike thwarted before it could land. His fists were a mess of demonic blood and bones.
Wounded and alarmed, Akaza fell back beside Douma, his eyes shrinking heavily, unable to hide the unease creeping across his face. Douma, though typically aloof, showed signs of desperation, his smirk completely gone. For the first time, they were up against a foe who felt utterly unstoppable.
After all, how could such a human exist? The Two Kizuki didn't even leave him with a scratch.
With one final, powerful step forward, Yoriichi brought down his blade, ready to sever the two demonic heads in one swing, the strike laced with enough force to break even the toughest demon skin. Douma and Akaza felt the burn of sunlight sear towards them, their bodies unable to mend under Yoriichi's eyes. The two demons crumbled, their forms dissipating under the purifying radiance of Yoriichi's Nichirin blade.
Or at least that was supposed to happen.
Moon Breathing: First Form—Dark Moon, Evening Palace.
The clash of two swords echoed, and Yoriichi's eyes widened in stunned disbelief, his expression shifting for the first time since the battle began. His blade had met with a warped, twisted sword—a weapon as unsettling as the figure wielding it. Sun and Moon clashed, and two techniques crossed after years of separation.
"Yoriichi." Six ominous eyes locked onto him, and Yoriichi felt a wave of despair crash over him as he took in the demon's face and the dark, violet-black haori. The demon's voice was calm, familiar yet burdened with something darker. "It has been... a long time... brother."
Kokushibo's gaze then fell upon the battered forms of the other two demons who shared his rank. His eyes, cold and piercing, held an air of disdain, disappointment radiating from his every glance.
"In the end, it was all useless," the demon murmured, his voice edged with bitterness. "The hierarchy exists not just to enforce order among demons but to create beings capable of defeating the strongest Demon Slayer. Yet, even against you, that strength means nothing. As always, you prove that no power can truly rival yours, Yoriichi."
"Your words are harsh, Kokushibo-sama!" Douma interjected, only to be completely disregarded.
Yoriichi's grip on his sword tightened, his hand trembling as he stood before the demon that wore his brother's face. His once cool resolve wavered as he took in the twisted sight of Kokushibo—no longer Michikatsu, yet unmistakably the brother he once knew. Sadness seeped into his voice as he finally spoke, his tone tender and fractured.
"Brother… why? What could have driven you to embrace this twisted form?" Yoriichi's words hung in the air, filled with both sorrow and disbelief. He had always known his brother's fierce ambition, but never did he imagine it would lead him here, to this monstrous transformation.
Kokushibo's six eyes bore into him with an intense coldness and hostility as if daring him to speak more. His voice was steady, but laced with something unspoken threat. Amidst was resentment and hurt pride wounded so deeply that only centuries of controlled hatred could conceal it.
"For centuries," Kokushibo began, his voice carrying a weight that hinted at his years of isolation, struggle, and bitter willpower, "I have slain countless humans, honing my techniques. I have given everything for one purpose—to surpass you, Yoriichi. To stand on equal ground. Yet, no matter how much I sacrificed, I remained nothing more than a shadow cast in your figure."
Yoriichi flinched, feeling the pang of his brother's jealousy and bitterness radiating from every word. There was a flicker of pain in Kokushibo's eyes, a trace of the brother he once loved, now buried beneath layers of betrayal and hate. Yoriichi's voice almost trembled as he replied.
"I never wanted this, Brother. I never sought to stand above you, my only wish was to walk beside you." The weight of those words seemed to land on Kokushibo, but his expression remained steely, unwilling to yield to the past they once shared. He stared impassively at the expressionless of his younger brother.
"Walk beside me?" Kokushibo echoed, his voice almost mocking. "You, the prodigy blessed by the gods themselves? You can't understand what it feels like to live in the shadow of your own kin, to be reminded every day that you were born lacking! Your gifts, your abnormal strength… they stripped me of everything! My pride, my honor… even my humanity!"
He glared impassively at the expressionless of his younger brother.
It didn't matter anymore.
That's what Kokushibo told himself.
Yoriichi's heart contorted, the words striking deeply. He had seen his brother's struggle, his yearning to be stronger, but he had never known the extent of Michikatsu's torment. Yoriichi's hand hovered, his grip loosening as the weight of his brother's pain pulled at him.
"I could never see you as anything less than my equal, Michikatsu," he whispered, using his brother's human name, a fragile reminder of who they had once been. "We were both given gifts. Though they may be different, both are worthy. I… I would have given anything for you to see yourself as I did."
Kokushibo's expression darkened, his face twisted with bulging veins and something dangerously close to grief. "Do not call me by that name!" he spat, his voice laced with venom. "I am no longer the man you remember. I am Kokushibo, and I have renounced all ties to my mortal past."
His life, his family, everything.
Yet even as he spoke these certain words, Kokushibo's voice wavered, and Yoriichi sensed the faintest hint of regret. He saw the flicker of something human in those six monstrous eyes, an echo of the brother who had stood beside him not long before he headed to complete the mission near that unsettling village. The contrast was so cruel to that image.
A silence fell between them, charged with tension and feelings left unspoken. Yoriichi's eyes softened, his heart heavy. "I never wished for you to feel this way… To carry such bitterness. But if your blade rises against humanity, I have no choice but to stop you."
I'm sorry.
Kokushibo's mouth twisted into a sore smile that didn't feel quite right for a reason he chose not to address. "Then draw your blade, Yoriichi. Let us see if the Sun's blessed one can finally be eclipsed."
Yoriichi and Kokushibo's forms vanished, leaving only disappearing afterimages in their wake. The air filled with the sound of steel meeting steel, the intensity of their battle a blur of strikes too rapid to be seen clearly. Their blades clashed with such force that each swing seemed to ripple through the corridors and walls of the Infinity Castle, the cuts embedding deep grooves in the demonic structure around them.
Sun Breathing: Fifth Form—Setting Sun Transformation.
Yoriichi's blade arced downward, glowing with a fierce, radiant glare, seeking Kokushibo with the precision of a legendary demon slayer. Kokushibo countered without hesitation, his own sword emitting dark, crescent-shaped slashes that erupted in every direction.
Moon Breathing: Sixth Form—Perpetual Night, Lonely Moon - Incessant.
Kokushibo unleashed a barrage of crescent slashes, each whistling through the air in deadly arcs, intent on overwhelming his brother. Yoriichi moved swiftly between them, his movements fluid yet purposeful, leaving only a glimmer of his form in each location he'd just evaded. His breath remained steady and calm—an anchor against Kokushibo's storm.
The impact of their blows sent shockwaves across the demonic fortress, causing walls to crack and floors to shudder beneath them. Dust and fragments of dark, enchanted wood fell from above as the structure groaned under the strain of their clash. Despite Kokushibo's relentless assault, Yoriichi maintained his focus, focused and deliberate as he moved closer.
Sun Breathing: Fourth Form—Burning Bones, Summer Sun.
Yoriichi swung in a wide arc, his blade wreathed in blazing sunlight. The strike seemed to sear through the air itself, aiming directly for Kokushibo's torso. Kokushibo barely parried in time, the force of Yoriichi's attack sending him skidding back, his expression momentarily faltering.
The Upper Moon One steadied himself, anger flashing across his six eyes. His hatred fueled him, his resentment a force that seemed to amplify his strength. With a dark glow in his six eyes, he prepared for another strike.
Moon Breathing: Seventh Form—Mirror of Misfortune, Moonlit.
Kokushibo's blade danced in complex, overlapping arcs, creating a barrier of crescent moons that whirled around him in defensive fury. Yoriichi, undeterred, pressed forward, weaving through the flurry of crescent-shaped cuts with an agility that defied nature itself.
This made Kokushibo's fury reach new levels.
Every step brought him closer, every breath steady and unwavering. Despite the strength of Kokushibo's defense, Yoriichi's form remained untouched, his blade striking through the barriers with pinpoint precision, dismantling each arc until he was face-to-face with his brother once more.
Yoriichi's eyes, full of sorrow and resolve, met Kokushibo's. He could see it now—the remnants of the brother he had once loved, twisted by centuries of envy and darkness. As their swords locked once more, Yoriichi hesitated for a moment, and downfall followed.
"It doesn't have to be this way, Brother."
Kokushibo's face contorted with rage, his voice a furious snarl. "Enough! I will not suffer your pity, Yoriichi!"
With renewed fury, Kokushibo unleashed another onslaught, Yoriichi met him blow for blow but was pushed back, their techniques colliding in a dazzling display of power. The Infinity Castle trembled as their battle escalated, but Yoriichi's blade seemed to slow a bit. He fought not as a warrior but as a brother.
Moon Breathing: Eighth Form—Moon-Dragon Ringtail.
With a swift, fluid motion, Kokushibo swung his twisted blade in a vast, circular slash, sending out several jagged, crescent-shaped projectiles. Each crescent was massive, the edges serrated and dark as they carved through the dimly lit space, aimed to encircle Yoriichi from all directions. These crescents rotated wildly, slicing through the air with an ominous, bone-chilling whistle as they approached their mark.
As Kokushibo and Yoriichi clashed, an intense surge of energy flooded the space, a new presence arriving in the shadows. Emerging from a tear in the sky above were two familiar to Kokushibo figures. It was Upper Moon Six, Gyutaro, and his demon sister, Daki, their expressions alight with eager malice to fight.
"Muzan-sama ordered us to kill the human!" Daki spat, her voice sharp and vicious, while Gyutaro glared at Yoriichi with palpable disdain.
"Is that him? Let's get this over with." Her brother said, glaring hatefully.
But before either sibling could make a move, they felt a murderous pressure crash down upon them, suffocating and inescapable. Kokushibo's six eyes glowed with a menacing intensity, his face twisted with demonic visage.
"Do not interfere," Kokushibo growled, his voice low and laced with lethal intent. "If either of you gets in my way... I will kill you both."
The threat of Upper Moon One carried an undeniable weight that neither Gyutaro nor Daki could ignore. Even as powerful demons themselves, they faltered beneath Kokushibo's terrifying gaze, shivering and feeling the promising truth of his words.
To Kokushibo, this battle was sacred. A clash he had waited centuries for, one he was certain would never come again. Yoriichi stood before him, still youthful, and as powerful as ever, a memory of old Yoriichi and a haunting reality merged into one.
In his brother's presence, Kokushibo's judgment solidified; no other demon, not even Muzan himself, would interrupt what was destined to be settled between them alone.
Yoriichi's eyes narrowed as he darted forward, barely grazing the edges of each deadly arc as they shattered against the floor and walls, leaving deep scars and splintering the enchanted wood into splinters.
Moon Breathing: Ninth Form—Waning Moonswaths.
Kokushibo lifted his sword and slashed in an upward motion, creating a rain of crescent-shaped slashes that fell upon Yoriichi. The projectiles filled the air, each with a lethal sharpness, descending with unrelenting force.
Yoriichi moved with impossible speed, deflecting the incoming crescents as some tore through the walls and platforms around them, casting shadows across his face. The wooden platform shattered under the weight of Kokushibo's power, pieces of the castle raining down as though they were mere paper before the relentless force of his attack.
They both moved to another one.
Yoriichi appeared unfazed, his expression unwavering as he defended against every attack. Kokushibo's frustration grew, his hatred flaring as he unleashed another assault.
Moon Breathing: Tenth Form—Drilling Slashes, Moon Through Bamboo Leaves.
Thick, dark mist engulfed his figure, turning him into a wraithlike silhouette, phasing in and out of sight like a vengeful shadow. Each step brought him closer, each movement hidden within layers of dark mist that shrouded his strikes.
Crescent moon arcs swirled around Yoriichi, the sharp edges slicing through the air, casting the illusion of a deadly labyrinth closing in from every direction.
Suddenly, one of Kokushibo's swift, phantom-like strikes found its mark. A thin cut opened on Yoriichi's cheek, a single drop of blood trickling down. For a fleeting moment, Kokushibo's expression twisted with shock and a hint of euphoria, as if he had finally achieved the impossible.
Hinokami's spilled drop of blood.
That drop of blood—proof that Yoriichi was human, that he could be hurt, that he might falter against the relentless onslaught of a demon who had spent centuries honing his skills along with hatred.
Gods don't bleed.
Fueled by dark exhilaration, Kokushibo's attacks intensified, his form accelerating to unimaginable speeds. He pushed forward, each slash accompanied by a dozen crescent arcs that multiplied in a frenzied storm.
The cuts whistled through the air, leaving silver trails that intersected and overlapped, forming a web of lethal force around Yoriichi. Each step of Yoriichi was blocked by an endless wall of crescents, each movement closed off by another assault from Kokushibo's blade.
For the first time, Kokushibo felt a surge of hope: perhaps he could finally overwhelm his brother's brilliance, perhaps he could stand victorious over Yoriichi, the sun that had always burned just beyond his reach.
Kokushibo's strikes were relentless, his Moon Breathing leaving an endless path of destruction around him. The once pristine haori of Yoriichi bore the marks of Kokushibo's assault, fraying at the edges, torn and scarred, a stark reflection of the emotional torment raging within.
To Kokushibo, this moment was a twisted culmination of his life's purpose—he was finally defeating Yoriichi, nearing the impossible dream he had chased for centuries: to match, even surpass, his younger brother.
But as their blades met, Kokushibo's six eyes widened as he glimpsed something unexpected in Yoriichi's face.
Tears flowed from his eyes.
He saw his brother's expression breaking, a raw anguish visible through the unwavering perseverance. Kokushibo felt a shudder through his demonic core.
The world around them seemed to fade as he realized: Yoriichi was holding back.
For Yoriichi, every strike tore at his heart, a clash of duty and love. This wasn't just a fight against another demon. Before Yoriichi was his brother, the one he had once cherished, who had stood by him from birth, who had shared his times of childhood. But now, as Kokushibo's monstrous form lunged at him, Yoriichi couldn't bear to strike with his full strength.
How could it have come to this?
The face of the man who had been Michikatsu flickered in Kokushibo's memory. He remembered the boy who had once envied Yoriichi's gifts but also admired him deeply, the brother who had tried so hard to stand by his side. He remembered, too, the day he had offered Yoriichi the flute, a gift that signified the bond between them—a bond now severed by his own choices.
But why? Why did he care now? Why, in the face of the one goal that had driven him for centuries, did these old memories creep back? The weight of his actions over centuries pressed down upon him, chilling the fiery hatred he had fostered. Have I spent my life chasing a hollow ideal?
Kokushibo's movements faltered, his attacks growing sporadic, the rage dimming in his eyes as the realization struck him: the hatred he'd harbored was shallow, an empty purpose to fill the void left by his brother's absence. He had been consumed by jealousy. The need to prove his worth to the world, but now, faced with Yoriichi's pained expression, he wondered.
Was it worth it?
Kokushibo felt a stabbing pain where his human heart had once beat. Somewhere along the way, he had lost himself, transforming into a demon, not for power, but in a desperate attempt to become something he thought he was missing. Is leaving the mark on the world truly that important?
As their blades met for the last time, Kokushibo's mind drifted, lost in a haze of regret and longing. Could I have chosen differently? Could we have both stood in the sunlight?
Kokushibo's intention cracked, the cracks widening with each remembered moment.
Why was I even born?
His twisted blade, once wielded with unmatched fury, now fell from his grip, landing on the ground with a hollow thud. For the first time, his face softened, stripped of hatred and malice, as he whispered words that carried the weight of centuries, a truth he had tried so hard to deny.
"Kill me, Yoriichi." The admission, raw and free of unhealthy pride, held within it the shattered remnants of an ambition he had clung to, now revealed as nothing more than pain.
Kokushibo's six eyes were uncharacteristically damp as he watched Yoriichi hold up something he hadn't seen whole as if in an eternity.
A small flute, broken and worn, yet still real in Yoriichi's careful hands. The same flute he had once held was not broken. He could barely speak as he looked at it. "Even after becoming a demon… you still cling to humanity?"
Yoriichi's face mirrored his sorrow. "We are both crying, brother," he whispered, voice barely audible but filled with a warmth that seemed foreign in this castle of darkness. Kokushibo was startled, and as he glanced at his own face reflected in Yoriichi's blade, he realized tears had begun to fall from his own eyes too—emotions in the form of liquid he'd thought to have buried centuries ago, now flowing freely.
The broken flute felt almost warm in Yoriichi's hand, a reminder of the days when they had stood side by side, pursuits unmarred by jealousy and fate. He held it out to Kokushibo, a silent offering of peace. "I've kept this flute… to remember you."
Kokushibo stared at it, the deep-seated bitterness within him wavering, an almost soothing sensation spreading through him. Even as a demon, Yoriichi still saw him as family. "Even after all this… you still call me brother?"
As the dust of Kokushibo's broken form began to scatter, it was no longer the proud, vengeful Upper Moon One that Yoriichi saw, but his older brother—Michikatsu—who finally returned, if only for a fleeting moment.
For what felt like an eternity, a genuine smile touched Michikatsu's demonic visage. It was a smile that, despite the monstrous appearance, felt pure. It was the smile of the man who had once grown up with Yoriichi.
"Thank you," he whispered, his voice no longer that of the wrathful demon Kokushibo, but of Michikatsu, filled with a quiet gratitude that transcended mere words. He reached out and held the flute in his hand. It was a cherished memory of his younger brother. Michikatsu's fingers gently traced its edges. He closed his eyes, holding onto that fragment of his humanity one last time.
Slowly, Michikatsu's body began to dissolve, fragments turning to dust as his form wavered. The head wasn't severed and his body wasn't under the sun and yet he started to crumble in incomprehensible means. Yoriichi watched, pain flooding his heart as his brother faded, piece by piece, into the air. It was as if the burden of centuries was finally lifting from Michikatsu's soul, leaving behind the peaceful remnants of the person he once was.
"Brother..." Yoriichi stood alone in the dim light, surrounded by nothing but remnants of dust—a fleeting reminder of the bond he had once cherished and the brother he had now lost forever.
At that moment, Nakime, Upper Moon Four, who had been observing from the shadows, sensed the finality of Kokushibo's defeat. After this devasting defeat, she needed to save her master from this monster.
Knowing her master's orders, she summoned an opening beneath Yoriichi's feet. But Yoriichi didn't move, his gaze fixed on the vanishing figure of his brother, his heart too heavy to acknowledge the shifting ground below.
He vanished from the Infinity Castle, leaving no trace of his presence, only remains of still regenerating demons, as if he had never stepped into its depths at all.
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Yoriichi found himself once again at the doorstep of the Kamado family. As he stood there, he was met with a warmth and relief that took him by surprise. The family members' weeping eyes and open arms told him of the connection they had felt toward him, a bond he hadn't realized ran so deep.
"Yoriichi-san, you look so sad," Tanjiro observed, his eyes reflecting a tender understanding beyond the simple boy.
Tanjiro is truly a caring boy, Yoriichi thought.
"Perhaps," Yoriichi admitted, the weight of his words heavier than he'd anticipated. "I am mourning a brother I lost today."
The words came unbidden, stunning even him, but he allowed them, a melancholy smile breaking through his usual composure. Perhaps it was time to embrace change and find solace in the company around him, he thought. After all, as Tanjiro reminded him in his gentle way, he was not alone.
Tanjiro's face widened in understanding as he absorbed Yoriichi's quiet confession. "Was he a good brother?"
"He was the best I could have ever asked for," Yoriichi replied, closing his eyes and feeling a flicker of warmth as he spoke.
Moved, Tanjiro offered his heartfelt prayer. "Then may he be at peace, wherever he is."
Yoriichi stayed with the Kamado family through the night, his silent vigil a reassurance that nothing would harm them until dawn finally broke over the horizon.
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In the morning, Tanjuro Kamado finally opened his eyes and woke up. A wave of relief washed over Yoriichi as he realized that the sudden demon attack had not claimed his life.
A celebration erupted as Tanjiro's younger siblings rushed to embrace their father, their joyful reunion filling the room and dispelling the atmosphere that had haunted them. Illness might soon take Tanjuro, but Yoriichi was certain: it would not be a demon that did so; he had vowed to prevent that.
"The Kamado family is grateful to you, Yoriichi-san. Without you, who knows what cruel fate might have befallen us," Tanjuro said, his voice filled with gratitude, even as it betrayed signs of exhaustion.
"I did what I had to do as a Demon Slayer," Yoriichi replied, his eyes unhesitating. "I hope your family will find happiness in the future, Tanjuro-san, Kie-san."
"Yoriichi-san!" Nezuko's sudden cry pierced the air, and the entire family turned to him with widened eyes.
Yoriichi was confused, not understanding the sudden horror in their gazes until he saw his body beginning to glow. His hands started to dissolve into a cascade of shimmering lights as if fading into the very air around him.
"It seems my time has come," he said with a calm heart, a soft smile gracing his lips. This was not his time to be here; his presence had been nothing short of a miracle.
Strangely, it felt odd to be disappearing, especially since he had again failed to fulfill his assigned task. A bitter thought flickered in Yoriichi's mind. Once more, he had let everyone down.
"Thank you, Kamados," he turned to Tanjiro, his voice delicate but strong, filled with gratitude. "Thank you for helping me realize the truth, Tanjiro." There was a hint of resolution in his voice, but also relief; he had finally found peace in these moments with a family that had become precious to him.
And just like that, in a brilliance that seemed to consume everything around him, he was gone. In his final moments, Yoriichi caught a glimpse of the family's expression, full of hope and gratitude. He understood then that his mission had not ended in failure but in success that would live on in the hearts of those he had helped.
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Yoriichi found himself standing once more, and above all, alive. He was taken aback when he realized he stood at the entrance to the village where he had eradicated the demon, the same place he had entered the mysterious forest and emerged at a different time.
"Have you seen enough?" A voice broke the silence, belonging to a small girl with white hair, whom he had seen before with the old fisherman. In the aftermath of everything that had transpired, the memory felt distant, as if weeks had passed since he had been here.
He knelt on the ground before the girl, bowing his head in reverence, displaying the weight of his soul and the knowledge he had gained.
"Thank you for showing me this path, Kami-sama."
Her smile was gentle yet enigmatic upon hearing his words, a flicker of expectancy in her bright eyes. "I'm glad. Perhaps this time shall be different, Tsugikuni Yoriichi. Knowing what is to come, what do you plan to do now?"
Yoriichi took a deep breath, the gravity of her words settling within him. He felt the pulse of the world around him, the whispers of the wind urging him forward, reminding him of his purpose. "I will not allow the past to repeat itself. I will protect those who cannot protect themselves. I will fight against the darkness correctly. I won't be alone anymore."
The girl's smile deepened, filled with an understanding that transcended their brief encounter. "Then go, Yoriichi. Let your actions echo through time to the distant destiny you seek."
With that, her figure faded into the mist, leaving behind a soft, glowing light that lingered in the air, as if granting him strength.
Yoriichi rose swiftly, determination fueling his steps. He left the place behind, feeling the weight of the future on his shoulders. The next day, as he ventured onward, the village had vanished, leaving no trace behind—only echoes of laughter and the distant hum of life that once thrived there.
In his heart, he carried the resolve to honor their memory, to ensure that their lives would not be in vain. Each step felt lighter as if the very earth beneath him encouraged his mission. He was no longer just a slayer of demons. He shall carve a new beautiful world for those who would come.
...
Michikatsu was beyond stunned when his younger brother, Yoriichi—who was supposed to be away on his mission—appeared out of nowhere with a rush of wind and embraced him with quiet tears glistening in his eyes.
In that brief moment, Yoriichi seemed vulnerable to Michikatsu more than ever, like a delicate thread holding memories too heavy for one person to bear. There was something profoundly different about him, something almost had changed, and Michikatsu found himself unable to pull away. He waited in silence, sensing the weight of something unimaginable that Yoriichi was about to share.
"It's good to see you like this, brother." Yoriichi finally spoke, his voice relieved and grateful to the world, as though he were witnessing a miracle. "Without… an extra set of eyes."
Michikatsu's brows knitted together in confusion until Yoriichi began to tell him the impossible story. He spoke of a demon that looked uncannily like him, only with pale skin and eyes full of hatred. The vision alone filled Michikatsu with a sense of nausea, but as Yoriichi continued, describing a hellish place.
His brother described a demon's lair with shifting walls and endless corridors of darkness. Michikatsu felt an unshakable dread settle within him. A demon could exist with such terrifying power? The thought alone was a seed of terror, one that took root and grew.
But worse was the knowledge that this demonic version of himself had fought Yoriichi to the death, mercilessly and full of hate that had only begun to gather lately. Michikatsu looked at his brother in horror, his hands clenched tight, feeling a sharp pang of guilt and something darker twisting within him.
His inner turmoil mirrored his worst fears; he couldn't ignore the gnawing doubt that perhaps, deep down, some part of him might become the very thing his brother had described.
And all of this had happened because of one man.
Kibutsuji Muzan. The Demon King.
The idea that Yoriichi, who had always been unnatural in his strength, had managed to battle such a demon seemed both awe-inspiring and deeply unsettling.
Michikatsu knew he would stand no chance against such an enemy, not even for a minute, and a wave of dark thoughts crashed over him. The ache of resentment surfaced, fed by his inability to surpass Yoriichi, his fists trembling with the frustration of knowing his body's limitations.
Then, Yoriichi's voice shattered his thoughts, gentle yet filled with unwavering resolve.
"Please, brother," Yoriichi pleaded, looking up at him with a rare intensity. "Help me defeat him."
Michikatsu's heart raced as he processed Yoriichi's request. He saw the earnestness in his brother's eyes, the vulnerability that, somehow, Yoriichi could only show him. For so long, he had lived in Yoriichi's shadow, burdened by his envy and resentment. But now, his brother was reaching out to him, seeking his strength as an equal, as someone he could trust in the battle against an unimaginable evil.
A flood of conflicting emotions surged within him. Pride, doubt, jealousy, and an unspoken love he'd suppressed long ago. Perhaps for the first time, his perspective shifted to time lost gone, Yoriichi who had always seen the best in him, even in his weakest moments.
Finally, Michikatsu gave a slow, determined nod, his voice a whisper.
"If you ask… I'll try my best, Yoriichi."
He knew it wasn't just a promise to Yoriichi. It was a vow to himself, however fleeting or uncertain the future might be.
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"That's him," Yoriichi said quietly, his gaze sharp as he stood beside his brother, facing the Demon King. Michikatsu followed Yoriichi's line of sight and saw the man with eyes the color of fresh blood. Muzan Kibutsuji stood there, his presence dark and imposing, with an eerie arrogance in his expression that was both disturbing and demonic.
Beside Muzan was a woman, another demon, her gaze blank and emotionless like a puppet or a servant bound to her master. Her pale skin and lifeless eyes only amplified the sinister aura surrounding the Demon King. It was as though she existed solely as an extension of Muzan's own will, poised to strike at his slightest command.
At least that's what Michikatsu thought.
Michikatsu felt his hand trembling on the hilt of his sword, his resolve battling the fear gnawing at him as Yoriichi gave him a steady nod, his calm presence a silent promise of their shared strength. There was no mistaking the fact that blood would be spilled here. Michikatsu's heart pounded as he realized the magnitude of what lay before them.
With a sickening crunch, Muzan's arms stretched, elongating grotesquely as the bones in his limbs twisted and contorted. A dark storm of razor-sharp attacks erupted from Muzan's body, his arms and back transforming into a whirling maelstrom of flesh and claws, tearing through the air with a vicious force that shattered nearby trees as though they were nothing but brittle twigs.
The sheer power emanating from Muzan sent a shiver down Michikatsu's spine. This was a demon unlike any he'd ever faced. And yet, he was here, facing it alongside his brother.
In another timeline, Yoriichi would have encountered Muzan alone, much later, when Muzan no longer felt threatened by any demon slayer. But now, confronted by the twin figures of the Tsugikuni brothers, Muzan recognized the threat that loomed before him. His expression darkened, the gleam of malice sharpening in his blood-red eyes.
The two brothers leaped into action as Muzan's tendrils lashed out with unrelenting fury. Yoriichi's movements were swift, almost imperceptible to Michikatsu. He darted and spun through the deadly onslaught with flawless timing, each motion calculated to a fraction of a second. His blade sliced through Muzan's reaching tendrils, a whirlwind of practiced cuts that left flashes of crimson in the air.
Michikatsu, fighting alongside his brother, was a significance of his own. Though he lacked Yoriichi's perfect grace, his raw power was formidable, his strikes precise and grounded. He parried the attacks Muzan threw at him though his bones cracked when doing so, narrowly dodging the twisted limbs that came barreling his way. Each movement demanded every ounce of his focus, his mind, and his body in forced unison as he fought to keep up with his brother's rhythm.
The brothers exchanged a brief glance in the chaos, a silent nod. With this Michikatsu charged forward, his blade cutting through the air with an intensity driven by years of rivalry, frustration, and ambition. He had never thought he'd be standing here, battling such an unspeakable horror with Yoriichi by his side, but now that he was, every strike felt as if it carried a lifetime's worth of resolve.
Michikatsu took a deep breath.
The mark on Michikatsu's face began to expand as the world around him seemed to narrow, sharpening into focus. Only then did he realize that he could now track the movements of his younger brother—movements he'd once thought too swift to follow. His speed surged, heart racing as he pushed his limits.
Moon Breathing: Second Form—Pearl Flower Moongazing.
Executing his technique, he unleashed a flurry of crescent-shaped slashes that sliced through the air, each one precise and deadly. With a series of cuts, he severed the demon's limbs, leaving Muzan reeling, his face contorted in shock and rage at the sudden sensation of having his body parts cut.
Yoriichi, seeing an opening, swept in with astonishing speed, his sword blazing as he struck with Sun Breathing's Second Form: Clear Blue Sky. His blade spun in a perfect arc, the force of the move creating a powerful shockwave that struck Muzan squarely, sending a ripple of energy through the demon's body. For the first time, Muzan's expression faltered a flicker of genuine alarm in his eyes.
Taking advantage of the moment, Michikatsu lunged forward, delivering a powerful, downward slash aimed straight at Muzan's chest. His blade struck true, cutting deep, but Muzan's regeneration was immediate, the wounds knitting back together even as Michikatsu's sword withdrew. The effort was exhausting, his breath ragged, yet he could not afford to hesitate.
Michikatsu seemed to reach Yoriichi's speed.
Muzan's fury exploded, and the ground trembled beneath them as he released an even more vicious barrage of attacks. The brothers were forced to move in perfect harmony, dodging, blocking, and countering with a synergy that defied their differences. In those few fleeting moments, they fought as brothers united against a common enemy, their movements synchronized with a bond deeper than words.
With every strike, every narrowly avoided attack, Michikatsu's affection for Yoriichi grew, even as the darkness within him dispatched, moved by the image of himself and his brother doing an impossible feat. Now it was the time to survive, to win, and to protect each other against the demon that threatened to consume them both.
Summoning the last of his strength, Michikatsu swung his blade with all his might, his attack merging with Yoriichi's as they struck in unison, creating a brilliant, lethal flash of power aimed straight at the Demon King.
Amid the storm of chaos and blood, Muzan's scream tore through the air.
Muzan's body shattered into a shower of flesh and fragments, scattering in every direction. Michikatsu's eyes widened in shock. No! How could any creature survive such destruction? But then he caught the determined, single-minded gaze of Yoriichi. His brother had known this would happen; he had prepared for it.
Yoriichi had endured much to reach this moment, and he was no longer caught off guard by Muzan's survival tactics. He understood the Demon King's persistent drive to escape death by bursting his body into countless pieces. This time, Yoriichi had created a technique crafted for this very contingency, a skill honed through countless battles and visions of Muzan's path of destruction.
A divine chorus echoed within Yoriichi's mind—a resonance of the thousands of souls who had suffered at the hands of the First Demon. Their voices fused, becoming a guiding light that strengthened his will and focused his power.
The moment he was born for. He had failed once.
He couldn't twice.
The counter Yoriichi had forged specifically for this battle, born from his encounter at the Kamado household, where he had glimpsed the dividing technique that Muzan would do to escape. He had discovered the trails, the remnants of future attacks etched into Muzan's aura—proof of how Muzan had survived this battle. The beast with seven hearts and five brains had evaded death once, but Yoriichi would not allow it again.
Yoriichi's mark burned with an intensity he had never felt before, as if the very sun resided within it. Time seemed to halt, the world holding its breath and trembling in reference to his power. The radiant light of the sun pulsed through his veins, and fierce flames emanated from his sword. His eyes, filled with the fire of judgment, locked onto Muzan's scattered remains, ready to incinerate every last trace of the Demon King.
Yoriichi set his heart ablaze.
Sun Breathing: Fourteenth Form—Brilliant Sunrise.
The very fabric of sound shattered, giving way to deaf silence as his blade cleaved through every fragment of Muzan's existence. Each swing of his sword ignited with the blinding radiance of dawn, turning the battlefield into a canvas of unrelenting light.
The pieces of Muzan's flesh, countless as they were, could not escape the fury of the sun. They crackled, ignited, and began to disintegrate, the intense heat of the glowing blade vaporizing them into ash. Shadows shriveled and dissolved in the blaze, Muzan's remains reduced to flickering embers that writhed in agony, no longer able to reform or escape.
In his final moments, Muzan's visage contorted in a grimace of pure horror, his essence filled with the realization of true annihilation as they faded into nothingness. His wail, a scream forged of centuries of malice and ambition, was consumed by the flames, erased from existence along with his demonic legacy.
Yoriichi stood in the smoldering ashes, his blade lowered, surrounded by a scorched silence that marked the end of the Demon King. Michikatsu joined him when the dawn broke, casting a warm, golden light upon them as if the sun itself bore witness to Muzan's ultimate defeat.
"T-Thank you! Thank you so much!" The demon woman, standing nearby and witnessing everything, had tears streaming down her face. Her words of gratitude were the last sounds heard before she and all the demons began to turn to ash.
Yoriichi and Michikatsu both collapsed, gazing at the rising sun. The warm light enveloped them as they looked toward the future.
The grim future was averted.
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Next Chapter: Epilogue