Chapter 86: The Complex Fourfold Poison...
Enjoy~~~
The battlefield had transformed into a literal meat grinder. It no longer resembled Japan; it looked like a fragment of hell itself had fallen onto the earth.
Terrifying collisions deafened the ears, while the shockwaves from the techniques ripped apart the ground and uprooted massive boulders. Even the air had become heavy, saturated with the smell of blood, burnt flesh, and ozone produced by the overwhelming spiritual pressure.
"Stone Breathing — Fifth Form!"
Gyomei swung his gigantic chain, smashing apart three of Muzan's flesh whips that lunged toward him. But their regeneration speed was horrifying. Although his crimson blade slowed the regeneration slightly, Muzan's attacks were endless!
"Damn this bastard! He never stops!" Sanemi roared, his face drenched in blood. "Wind Breathing — Seventh Form!"
Sanemi burst forward, attempting to flank Muzan, but ten elite demons intercepted him, unleashing Blood Demon Arts in the form of poisonous spikes and acidic waves.
"Don't lose focus, Shinazugawa!" Rengoku shouted as he intervened like a flaming comet, decapitating five demons in a single circular strike. "Set your heart ablaze! We are this world's shield now!"
The Hashira fought ferociously, surpassing human limits entirely. Crimson blades illuminated the darkness, while the Demon Slayer Marks burned across their faces, granting their bodies indescribable power.
But…
Reality was cruel.
Muzan was not merely a demon.
He was a natural disaster.
Dozens of flesh whips covered in blades and mouths that released shockwaves erupted from his back and thighs at lightning speed.
Each whip carried enough force to slice a building in half, and his attack range covered such a terrifying area that approaching his neck was like trying to embrace a storm made of blades.
And alongside Muzan stood nearly one hundred elite demons launching suicidal assaults to obstruct and exhaust the Hashira.
Far from the center of battle, behind the ruins of a destroyed house, Tamayo watched the massacre with trembling eyes.
Blood flowed around her while the screams of warriors echoed in her ears. Both hands tightly gripped a large modified glass syringe filled with a dark violet liquid.
This was not merely poison.
It was the crystallization of centuries of hatred, despair, and research.
It was the "Complex Fourfold Poison" she and Shinobu had created—the final secret weapon remaining after Ren's fall.
The poison consisted of four deadly stages:
First: Turning a demon into a human.
Second: Rapid cellular aging at an insane rate—fifty years per minute.
Third: Preventing division and escape, nullifying Muzan's ancient trick used against Yoriichi.
Fourth: Destroying cells and collapsing the body from within.
"But… what use is the strongest poison if I can't deliver it to the target?"
Tamayo thought despairingly, biting her lower lip until blood dripped down her chin.
"His attack range is impossible to breach. The Hashira are barely surviving as it is. Any attempt to approach means I'll be torn into hundreds of pieces before I even reach ten meters from him!"
"We need an opening… just one second! One second where Muzan focuses his attacks elsewhere!"
Tears gathered in Tamayo's eyes.
Would everyone's sacrifices be wasted?
Would that boy, Ren, die for nothing?
"I'll give you that opening, Doctor."
Tamayo's eyes widened as she turned around.
From within the dust and shadows emerged Hakugi—the former Upper Moon Three, Akaza.
His human body was covered in bruises and deep wounds from his previous battle against Kokushibo and from protecting the wounded. Blood soaked his torn clothes.
But his eyes…
His eyes burned with a determination that did not belong to the world of the living.
He wore gauntlets reinforced with Nichirin metal and carried the short sword Ren had given him.
"Hakugi-san… you're human now! Your body doesn't regenerate anymore! Going in there is guaranteed suicide!" Tamayo shouted in warning.
Hakugi smiled softly, sadly.
He looked up toward the smoke-filled night sky and remembered a single face…
Koyuki.
He remembered the warmth of her hands.
He remembered the promise he made to protect her—and how he failed.
He remembered how Ren dragged him out from the depths of hell and madness, restoring his humanity and memories.
"I lived for hundreds of years as a demon, killing and destroying for nothing but emptiness," Hakugi said quietly. "That boy, Ren… he gave me back my soul. He gave me the chance to die as a human, and to atone for my sins so I can face Koyuki in the next life without shame."
Hakugi turned toward Yushiro, who stood beside Tamayo, pale with fear and concern for his mistress.
"Yushiro… use your concealment papers on Lady Tamayo. Hide her aura, scent, and existence completely. Once I break through his defenses, there'll only be a fraction of a second. Don't hesitate."
Yushiro nodded silently.
He pulled out a paper talisman and attached it to Tamayo's forehead.
The next moment…
Tamayo vanished completely from sight.
"Well then… let's fight one last time!"
Hakugi inhaled deeply, filling his exhausted human lungs.
He took the stance of the Soryu martial style—
And launched himself like artillery fire!
"Human Destruction Style — Broken Compass!"
Hakugi shot past the Hashira at a speed that stunned them.
"What is that idiot doing?!" Obanai shouted as he watched Hakugi charge directly into the center of the storm of whips.
Muzan sensed someone approaching.
With a gaze filled with contempt and rage, he recognized the attacker immediately.
"Akaza! You traitorous dog! You dare stand before me in that weak, fragile human body?! I'll tear you apart so badly even dogs won't recognize you!"
Five terrifying whips shot toward Hakugi at supersonic speed.
As a demon, Akaza would have dodged them effortlessly—or simply regenerated.
But as a human…
His eyes could no longer fully follow their speed.
His body was far heavier.
Yet the instinct…
The pure combat instinct refined over centuries had not disappeared.
Hakugi twisted his body at an impossible angle, barely avoiding the first whip as it sliced away part of his left shoulder in an explosion of flesh and blood.
He did not stop.
He did not scream.
Using the second whip as a foothold, he kicked off with enough force to shatter the bones in his right foot, launching himself high into the center of Muzan's defenses.
"Die!" Muzan roared, sending three more whips to shred him midair.
"Destructive Technique — Crushing Kick!"
Hakugi concentrated every ounce of remaining strength into his fist and leg, colliding directly against the whips.
With a horrifying crack of breaking bones, Hakugi's right arm was torn apart completely, while another whip pierced through his side and burst out from his back.
Hakugi spat a fountain of blood—
But…
He succeeded in forcing the three whips backward with suicidal strength, creating a tiny opening—
A temporary crack in Muzan's absolute defense.
"NOW!!"
Hakugi screamed as he fell toward the ground, blood pouring from him like a waterfall.
At the exact moment Muzan focused all his rage and attention on tearing Hakugi apart—
The concealment talisman fell from Tamayo's forehead.
Tamayo appeared from nothingness directly before Muzan's chest, inside his shattered defense perimeter.
Muzan's eyes widened in horror and shock unlike anything he had felt since facing Yoriichi.
"You?!"
Muzan tried to retract his whips—
But it was already too late.
In desperation, a short whip erupted from Muzan's shoulder and pierced through Tamayo's body, stabbing deep into her stomach.
Tamayo coughed blood directly into Muzan's face—
Yet she did not retreat even a millimeter.
Instead, she used her impaled body to pull herself even closer.
With a smile filled with hatred, vengeance, and bitter triumph, Tamayo stared directly into Muzan's terrified eyes.
"Do you remember me, Muzan? I have waited for this moment… for hundreds of years! Go to hell with me!"
Tamayo raised her hand and, with all her strength, drove the gigantic syringe directly into Muzan's chest, piercing his heart.
She slammed the plunger down—
Injecting the entire Complex Fourfold Poison into his bloodstream.
"AAAAAAAAAAAAAAAAAGH!!"
Muzan released a scream so horrifying it shook the earth itself—a scream of genuine pain and terror.
He struck out violently, ripping apart Tamayo's body and throwing her away like a broken doll, shattering the empty syringe lodged in his chest.
Tamayo crashed to the ground, her body torn apart, while Yushiro screamed her name through tears.
Hakugi collapsed nearby, bleeding to death—
But smiling as he stared at the sky.
They had accomplished the impossible.
Muzan staggered backward, clutching his chest.
"What… what did you do to me, you filthy bitch?! Poison?! It's not working! I'll destroy it within seconds!"
Muzan attempted to dismantle the poison using his cells—
But suddenly…
He dropped to one knee.
His body began feeling unbearably heavy, as though he carried an entire mountain. His hair faded into grayish white, and his skin started wrinkling.
His breathing became uneven.
"What is this?! I'm aging! My cells are dying instead of regenerating! This isn't ordinary human medicine… it's destroying my entire demonic structure!!"
Muzan thought in hysterical terror.
He attempted to split apart and escape—
But his cells refused to divide.
The poison prevented separation.
The moment the Hashira saw Muzan kneel and his whips noticeably slow down, they realized the golden opportunity before them.
"Lady Tamayo and Hakugi succeeded! Attack now!" Sanemi roared as he charged forward.
But before Sanemi could reach him—
A streak of pure fire passed beside him.
A warm, radiant aura like the morning sun melted the frost from everyone's hearts.
It was Kamado Tanjiro.
Tanjiro breathed deeply and steadily, his chest rising and falling in perfect rhythm.
His eyes contained no anger.
No hatred.
Only terrifying calm.
He had fully awakened the Transparent World.
Through his vision, Tanjiro saw Muzan's transparent body.
He saw the seven hearts and five brains destabilizing and weakening under the poison's effects.
At that moment, Tanjiro remembered all of Ren's brutal training.
He remembered Ren screaming at him while beating hidden potential out of him.
"Sun Breathing… isn't merely twelve separate forms. It's a dance. A continuous dance that never stops from sunset until sunrise. The first form connects to the second, the second to the third… until the twelfth reconnects back to the first… forming an endless cycle of flames that eradicates demons!"
Tanjiro closed his eyes briefly—
Then opened them.
His grip tightened around his blade, now glowing crimson so intensely it looked molten.
"Sun Breathing — Thirteenth Form!"
Tanjiro launched forward.
He was no longer human.
He became a true dragon of blazing fire.
He began with the Dance of the Fire God.
A horizontal slash severed two whips.
A spinning strike deflected an incoming attack.
A swift twist drove a deep thrust into Muzan's chest.
A backward flip carved through more flesh.
A continuous dance—
Never stopping.
Growing faster and hotter with every second.
"YORIICHI!!"
Muzan roared in blind terror as Tanjiro's glowing form overlapped with the monster who once terrified him in the past.
Muzan began unleashing his remaining whips wildly and chaotically.
"Support Kamado! Don't let a single attack touch him! He's the one who will sever this bastard's head!"
Gyomei roared.
Together with Rengoku, Tomioka, and Sanemi, he formed an unbreakable wall around Tanjiro.
They endured the blows.
Their blood spilled.
Their bones shattered.
But not a single whip interrupted Tanjiro's endless dance toward Muzan's heart.
…
Amid this storm of fire, blood, despair, and hope…
Far behind the battlefield ruins…
A strange silence dominated one small corner.
Yukihara Ren's body still lay motionless on the ground, cold and pale like snow.
Tengen sat beside him silently wiping blood from his weapon, prepared to die as the final line of defense if the Hashira fell.
At the same time, he protected Eri…
For the sake of her older brother.
Eri still sat beside Ren's head.
She no longer screamed.
She simply pressed her small forehead against Ren's cold one while tears continued endlessly soaking his bloodstained white hair.
"Onii-chan… you promised you wouldn't leave me alone again…" Eri whispered shakily while clutching his shirt. "You've fought enough. Please… wake up."
A warm tear rolled from Eri's eye and slowly fell onto Ren's closed left eyelid.
And at that moment…
Something happened.
Tengen did not notice it.
But from the corner of Ren's closed eye, it was not a tear that emerged—
It was a new drop of blood.
Dark.
Thick.
As the blood slid down his pale cheek…
A strange aura began forming.
It was neither golden like sunlight nor red like demonic energy.
It was black like the night itself, tinged with an extremely faint blue glow.
It was the remnant of cursed energy buried deep within his soul.
Inside Ren's shattered body—where organs had stopped and cells had burned away beneath the burden of the Six Eyes and Hollow Purple—
That black aura wrapped itself around his silent heart like threads of living darkness.
[Reverse Cursed Technique]
Ren remained unconscious…
But the pure instinct for survival gathered from all his lives and templates converged in this moment.
Cursed energy began generating pure positive energy—not to heal external wounds, but to reignite the very first spark of life itself.
Thump…
It was an incredibly faint sound, far too weak to hear amidst the explosions and chaos of battle.
But Eri, whose head rested against his chest…
Slowly widened her eyes.
She lifted her head slightly, holding her breath in disbelief.
Then she pressed her ear directly against his dead heart.
One second passed…
Two…
Thump… Thump…
A faint sound.
A slow, heavy, inhuman heartbeat.
Then another.
Yukihara Ren's heart had begun beating once more…
Slowly rising from beneath the ashes of death itself.
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