For a heartbeat, there was only silence.
The air within the Infinity Castle carried a suffocating weight, as though the walls themselves were leaning down to crush every intruder within. Lanterns swung on invisible threads, their crimson glow washing over the thousands of demons now filling the chamber like a tide of death.
Tanjiro's hands shook as he tightened his grip on his blade. His lungs felt heavy, yet the faint ember in his heart burned steady. Nezuko clutched his sleeve, her growl low and protective.
Beside him, Inosuke cursed and spun his blades in defiance. Zenitsu trembled, though his eyes darted about with sharp awareness, his breath quickening as he steeled himself for what was to come.
The Hashira were silent for only a moment.
Rengoku, his body still mending from wounds past, raised his voice, fierce and unyielding."Steady yourselves! This place may be the heart of the enemy, but it changes nothing—our blades exist to carve through the darkness!"
Tengen smirked even in the face of despair, his dual blades flashing. "Flashy stage, flashy stakes. Fine by me."
Shinobu's eyes narrowed, her poison-coated blade drawn with clinical calm, while Tokito and Mitsuri stood shoulder to shoulder, their breathing even as their gazes cut across the endless field of demons.
Slowly, the Demon Slayers found their footing. What began as shock turned into grim determination. The Corps had faced overwhelming odds before—but this was different. This was the end.
At the far edge of the platform, the Upper Moons stirred. Kokushibo's six eyes gleamed with cold dispassion. Douma's smile was serene, mocking. Akaza's fists clenched, his gaze sweeping toward Tharion with a memory of humiliation burning in his chest.
And above them all, Muzan rose from where Tharion had slammed him into the wall, his expression twisting in venomous rage.
"You…" Muzan's voice was ice and fire, his hand pressing against the glowing seal that restrained him. "You dare drag me into my own domain, and bind me here?"
Tharion stepped forward.
For the first time since his arrival in this world, the mask he wore seemed almost unnecessary—his presence alone radiated like a star about to collapse. The ground beneath his feet cracked, and the air thickened until every breath burned.
With deliberate calm, he reached for the invisible chains within himself.
[System: Power Limiter – Disengaged.]
The effect was immediate.
Flames erupted around him in an expanding dome, searing the nearest demons into ash with a single pulse. The fire did not consume him—it obeyed him, bending and coiling with his every breath, as if the world itself acknowledged his will.
Every step he took set the ground ablaze. Every movement carved arcs of fire through the air. He was no longer merely a warrior; he was an inferno given form.
Demons screeched as the fire dome expanded, their bodies incinerated in waves. The oppressive darkness of the Infinity Castle was forced back, light flooding the chamber in defiance of Muzan's dominion.
"Burn… everything," Tharion's voice thundered, each word carrying the weight of command.
The Hashira did not falter. They surged forward, their blades igniting with the breath of their forms. Rengoku's fiery arcs clashed against Akaza's fists, Mitsuri's whip-like blade wrapped around one of Hantengu's clones, and Tokito's mist sliced into the ranks of lesser demons. Tengen, with his twin swords flashing like thunder, cut down hordes with each flamboyant strike.
Tanjiro and his companions charged beside them, each step carrying the memory of every struggle they had endured. Nezuko leapt into the fray, her claws raking through the swarm, her blood igniting into flames.
And above it all, Tharion's firestorm raged.
He moved not as a man, but as a blazing titan, each slash of his blade carving through dozens, each breath turning the air itself into a weapon. The dome of fire pulsed outward in rhythmic waves, forcing the Upper Moons to adjust their footing, their eyes narrowing at the overwhelming display.
Muzan's fury only deepened.
"You think this fire can cage me? You are nothing more than a flicker—I am eternity!" he roared, his body shifting, writhing with monstrous power.
Tharion raised his blade, the flames coiling tighter, denser, until the heat was suffocating.
"No," he replied coldly. "Tonight, eternity burns."
The throne of nightmares had become a battlefield of fire. And the true war had only just begun.
The Infinity Castle pulsed like a living nightmare, its walls shifting with every tremor of battle. Screams of demons split the air, drowned by the roar of fire, steel, and will. The Demon Slayer Corps had been thrust into the lion's den—and yet, against the thousands that swarmed them, they did not falter.
The Hashira cut paths like storms given human form.
Mitsuri's whip-blade lashed across the horde, slicing dozens at once, her movements fluid and fierce despite the overwhelming numbers. Every swing painted arcs of pink light in the air, her heart hammering with determination not to let anyone behind her fall.
Tokito's mist veiled the battlefield, giving cover to the younger slayers. Through it, his blade flashed like phantom steel, cutting down demons before they could even realize he was there. For the first time, his movements carried a passion that echoed the memory he had reclaimed—his blade was no longer just skill, but conviction.
Tengen carved through the swarm with flamboyant precision, dual blades roaring like thunder. Each strike carried explosive sound, sending shockwaves rippling through the mass. His laughter, wild and unrestrained, filled the chaos. "Now this is flashy!"
And Rengoku—his presence burned brightest. Every swing of his flame-breathing katana left trails of fire that refused to fade, carving open the horde and setting alight the battlefield. His voice thundered encouragement to the younger slayers, rallying them in the chaos.
But the demons were endless. For every horde cut down, more rose from the walls, summoned by Muzan's will. Their claws and fangs tore through the mist, their screeches drowning out even the sound of battle.
"Hold the line!" Rengoku roared.
Tanjiro fought shoulder to shoulder with Inosuke and Zenitsu, the trio slashing their way through the tide. Nezuko's blood flames burned through the darkness, shielding her brother as he pressed forward. Even the unseasoned slayers, those whose blades trembled, held fast—because if they faltered here, there would be no tomorrow.
And amidst the chaos, the great predators moved.
Akaza's fists tore through the flames Rengoku hurled at him, the memory of their first battle carved into both men's hearts. Their eyes locked, and without a word, the battlefield seemed to clear for them. With a bellow, Akaza charged—and Rengoku met him with the roar of flame. Their rematch began in a storm of fire and fists.
On another front, Douma laughed as icicles bloomed in a storm of death around him. His voice was smooth, mocking, as he twirled amidst the carnage. "Ah, the insects dance again." Shinobu faced him with burning eyes, her blade flashing with precision, her movements sharp and venomous. Their clash painted the battlefield in frost and poison, beauty and horror colliding.
Kokushibo stood apart, his six eyes taking in the battlefield with predatory calm. He could see every form, every breath, every sliver of hesitation among the slayers. None, it seemed, were worthy of his attention. His blade remained sheathed as his gaze swept the chaos—until it fell on one man.
Murata.
The rank-and-file slayer stood bloodied but unbroken, blade clutched in trembling hands as he cut down yet another demon rushing at his comrades. He was no Hashira, no prodigy. To Kokushibo, he was nothing but a speck.
And yet—something flickered.
For a moment, Murata's stance shifted. His breath steadied, his movements sharpened. The edge of his blade gleamed in a way that even Kokushibo's many eyes could not dismiss.
Kokushibo's lips curled, his hand moving to his hilt."Curious… Perhaps there is more to you than a gnat."
The world around Murata seemed to fade, replaced by a surge of instinct buried deep within his blood. A resonance stirred, as if the battlefield itself demanded he rise. His lungs expanded with a clarity he had never known, and in that instant, his blade no longer felt like iron. It felt alive.
The air shivered.
And for the first time in centuries, Kokushibo felt something rare—anticipation.
The battle raged around them, but in that frozen moment, a predator had found his unexpected prey.
And Murata… had just awakened.