After the Death of Upper rank 4 Demon the infinity castle is collapsed and every body is teleported to different locations, Akaza, Giyu, and Sanemi teleported near a waterfall under the moon light.
The air was thick with tension as the three warriors stood facing one another under the blood-red moon. Akaza, the Upper Rank Three demon, stood tall and poised, exuding an aura of malevolent power. His red eyes gleamed with arrogance, knowing the formidable Hashira before him would offer a challenge unlike any other. Giyu Tomioka, the Water Hashira, and Sanemi Shinazugawa, the Wind Hashira, prepared for the battle that would decide the fate of the world. The time had come to end this demon's reign of terror.
Akaza's eyes narrowed as he swiftly entered his Technique Development stance (Jutsushiki Tenkai), ready to unleash his full strength. With a sudden burst of speed, Akaza dashed forward, his fists glowing with destructive shockwaves that shattered the air itself.
Giyu, eyes calm and focused, was the first to act, his hand gripping his Nichirin sword as the Water Breathing surged through him.
"First Form: Water Surface Slash!" Giyu cried out, delivering a swift, powerful slash aimed directly at Akaza's chest.
Akaza effortlessly sidestepped the attack, a mocking grin on his face. "You're too slow, Hashira," he taunted, his foot snapping out to meet Giyu's side with a shockwave strong enough to send him skidding across the battlefield.
But Giyu recovered quickly, his body already in motion, responding with Second Form: Water Wheel, launching into a spinning sword strike aimed at Akaza's head. The force of the attack created a vortex of slashes, but Akaza's lightning-fast reflexes allowed him to deflect the strikes with a barrage of shockwaves from his fists.
Sanemi, having watched the exchange with razor-sharp focus, didn't hesitate to join the fray. With a roar, he activated his Wind Breathing, his body a blur of motion as he streaked forward, creating a fierce gale with every step.
"First Form: Dust Whirlwind Cutter!" Sanemi unleashed a rapid series of slashes, sending shockwaves of wind crashing towards Akaza. Each slash created a cyclone-like effect, cutting through the air and threatening to overwhelm the demon.
Akaza countered with his Disorder technique, sending massive shockwaves from his body, but the relentless onslaught of Water and Wind Breathing strikes kept him on the defensive. With every movement, Akaza's eyes glowed brighter, his Compass Needle activating to sense the will of his opponents, honing in on their attacks and predicting their next moves.
Akaza leapt into the air, launching his devastating Annihilation Type lunge at Giyu, his fists glowing blue with destructive power. Giyu, anticipating the attack, summoned his Eleventh Form: Dead Calm to create an impenetrable zone of tranquility around him. The shockwaves from Akaza's punch collided with the defensive barrier, and for a moment, everything fell silent.
But it was only a fleeting respite. Akaza's Leg Type: Explosive Flurry began, and his legs became blurs as he kicked rapidly, each strike sending afterimages that could confuse even the most skilled swordsman. Giyu barely evaded, but a few of Akaza's kicks landed, sending shockwaves that caused his body to bleed.
Sanemi, using his sharp intuition, slashed with Seventh Form: Gale – Sudden Gusts, unleashing a flurry of wind slashes that overwhelmed Akaza. But the demon's Leg Type: Flying Planet Thousand Wheels struck back, sending a powerful upward kick that launched both Giyu and Sanemi into the air.
Realizing that this battle would not be won with speed and power alone, Giyu and Sanemi exchanged a brief, silent nod. They had to end this now, or risk falling to Akaza's relentless onslaught.
With determination burning in their hearts, both Hashira entered their final forms. Giyu's Demon Slayer Mark erupted into fiery light, his sword glowing red as he focused all his energy into one final strike.
Sanemi, too, unlocked his Demon Slayer Mark, his strength magnified to unimaginable levels. His sword turned red, matching Giyu's, as he prepared to strike the fatal blow.
"Ninth Form: Idaten Typhoon!" Sanemi roared, spinning rapidly and creating a tornado of slashes that tore through the air, devastating Akaza's defenses. The winds howled, and Akaza struggled to keep up with the barrage of strikes, his body being shredded by the force of Sanemi's wind.
Giyu, using the opening created by Sanemi, slashed with his Tenth Form: Constant Flux. Each rotation of his sword increased in power and speed, becoming a torrent of unstoppable strikes. The red blade glowed brighter as it connected with Akaza, slicing through his defenses and weakening his regenerative abilities.
Akaza, visibly weakened but far from defeated, tried to fight back with his Final Form: Blue Silver Chaotic Afterglow, unleashing hundreds of shockwaves in every direction. The battlefield became a storm of blue energy, overwhelming everything in its path.
But Giyu and Sanemi were ready.
With synchronized precision, the two Hashira launched their final strikes.
"Fifth Form: Blessed Rain After the Drought!" Giyu whispered, his blade descending with mercy, but no less power. The slash was a decapitating blow, aimed for Akaza's neck.
At the same time, Sanemi shouted, "Eighth Form: Primary Gale Slash!" His sword swung horizontally with such force that it cleaved through the air like a mighty gust of wind, cutting through the shockwaves and towards Akaza's chest.
In one final, unstoppable movement, the two blades collided with Akaza in a devastating display of power. His body, unable to regenerate in time, was torn apart. The shockwaves from his final attempt to fight back were drowned in the combined force of their strikes.
As Akaza's head fell to the ground, his body disintegrated into ash, the shockwaves of his death echoing through the ruins. The battlefield fell silent, save for the heavy breaths of the two Hashira. Their bodies were battered and broken, but the demon had been defeated.
Giyu Tomioka and Sanemi Shinazugawa stood victorious, knowing that their combined strength had finally ended the reign of Upper Rank Three, Akaza. But they knew the war was far from over—Muzan Kibutsuji's death was the only true end to the Demon Slayer Corps' struggles.
Still, in this moment, they had triumphed. And for now, that was enough.