Emotions were not something mystical.
They were chemical reactions.
Fear, despair, anxiety, and even joy, each was triggered by specific neurotransmitters and hormones released in precise, measurable patterns. Adrenaline accelerated the heart and sharpened perception. Cortisol-induced stress and dread. Imbalances in serotonin led to despair, while misfires of dopamine created confusion and instability.
In humans, the brain regulates these chemicals carefully.
Even in demons, that regulation normally worked just fine.
But Dōma was special.
His neural pathways, those responsible for emotional processing, were inactive. Not damaged. Not destroyed. Simply… unused.
Akira's poison did not introduce anything foreign into his body.
It contained only compounds that already existed within him, refined and stabilized precursors, carefully tuned catalysts that forced those dormant pathways to activate all at once. No toxins. No corrosives. Nothing his body could recognize as hostile.
To Dōma's cells, it was indistinguishable from his own natural biochemistry.
That was why he never noticed.
His regeneration did not reject it.
His adaptation did not counter it.
His instincts did not warn him.
Because the poison never attacked his flesh.
It attacked the silence inside his mind.
Once those chemicals flooded his system simultaneously, fear without context, despair without reason, anxiety without escape, his brain had no framework to process them.
Humans learns emotions over the years.
And Dōma was forced to experience them all at once.
The result wasn't pain.
It was an overload.
Fear, pure and undiluted, surged through him. If he had been able to stop, even for a moment, and calmly analyze what was happening, he might have realized the truth. But Alpha never gave him that chance. The relentless pressure, the constant attacks, left him no time to stabilize his thoughts or emotions.
So he panicked.
Completely.
When one of the ice dolls finally blocked Alpha's path, Dōma felt a brief, fragile sense of relief, as if he had been given a single breath to recover.
And in that instant…
Someone appeared behind him.
"Insect Breathing, Dance of the Centipede: Hundred-Legged Zigzag."
It was Shinobu.
She had somehow outrun the ice doll she was engaged with, her speed now far beyond before, amplified by her Demon Slayer Mark. Her movements became a rapid zigzag, an erratic pattern that shattered prediction itself. Each step confused Dōma's senses as she closed the distance in an instant, driving straight for his neck.
The thrust carried the full momentum of her speed.
Dōma realized it a split second too late.
The sheer footwork alone was powerful enough to tear apart an entire wooden bridge.
Before he could properly react, Shinobu stabbed him, cleanly, precisely, and injected poison.
"It's her…" Dōma thought. "She's fast."
"Insect Breathing—Dance of the Horsefly: Enticing Slash."
Shinobu leapt from a vertical surface, launching herself forward in a sharp thrust. In the next instant, she surrounded him with a dizzying swarm of stabs from every direction. Each movement redirected Dōma's counterattacks, slipping through the smallest openings in his defense and flooding his body with even more poison.
The assault was relentless.
And then.
Alpha shattered the ice doll that blocked its path and rushed in, closing the distance as it charged straight at Dōma.
And after being injected with layers of poison and pressed relentlessly by Alpha's assault, Dōma finally broke.
Panic surged through him, raw and unfamiliar, and in that instability, he unleashed his strongest technique.
"Blood Demon Art—Rime: Water Lily Bodhisattva."
An enormous Bodhisattva statue rose into existence, formed entirely of ice, vast and imposing, surrounded by blooming frozen lotuses. Dōma retreated instantly, taking refuge atop a lotus perched on the statue's shoulder.
The moment it fully manifested, the Bodhisattva struck.
A massive frozen fist came crashing down.
Both Alpha and Shinobu reacted at once. Alpha managed to evade cleanly, but Shinobu wasn't as fortunate; flying debris slammed into her, bones cracking under the impact. Before she could recover, the Bodhisattva's other hand descended toward her.
She didn't have time to dodge.
At that instant, her backup arrived.
"Thunder Breathing—First Form: Thunderclap and Flash!"
"Beast Breathing—Second Fang: Slice!"
"Flower Breathing—Second Form: Honorable Shadow Plum!"
Zenitsu, Inosuke, and Kanao burst onto the battlefield together. Their combined assault tore into the ice structure, shattering large sections of the Bodhisattva. Alpha followed immediately, striking with all six swords at once, forcing the statue to stagger backward.
Shinobu, catching her breath, asked sharply, "What happened to the ice dolls?"
Inosuke shouted, "THEY ALL BROKE FOR SOME REASON!"
Kanao added calmly, "After he started to panic… all of them broke."
Shinobu's eyes narrowed. "Then maybe… he can't maintain them without concentrating."
Even as she spoke, the shattered hand of the Bodhisattva began to reform, ice crawling back into place as the broken sections healed once more.
"It's getting back up!" Zenitsu shouted.
Shinobu didn't hesitate. She pulled out a small vial filled with blue liquid and drank it in one motion. Almost immediately, her injuries healed, her cracked bones knit themselves together, bruises faded, and the pain vanished at a visible speed. Akira's healing potion worked well, and Shinobu straightened, steady once more.
At the same time, the ice Bodhisattva rose again.
Its massive arm swung toward them, forcing everyone to scatter and dodge in different directions.
"What should we do?!" Zenitsu yelled. "It's too strong!"
"We need to find an opening," Shinobu said calmly, eyes fixed on the towering figure. "Or make one."
Before anyone could respond, the Bodhisattva opened its mouth. A torrent of freezing breath burst forth, flooding the corridor with killing cold. Everyone was forced back under the pressure, narrowly avoiding the blast.
Because of that brief reprieve, Dōma began to regain a fragment of his composure.
But Alpha had already decided.
There was no more room for delay.
He had to finish it right here, right now.
SYSTEM: OVERDRIVE MODE ACTIVATED.
The air around Alpha distorted as heat surged outward.
Its solar reactor roared at full power. The jet-black armor glowed red-hot, veins of light running through it, and all six blades ignited, burning a brilliant crimson. In the next instant, Alpha blasted forward.
The ice Bodhisattva opened its mouth, unleashing another freezing breath.
It didn't matter.
The solar reactor's heat vaporized the ice on contact. Alpha tore through the attack without slowing, its six swords carving into the massive statue. Ice shattered like glass, melting and splitting apart as if it were butter before a hot knife.
The Bodhisattva was torn apart in seconds.
Dōma saw it and turned to run. "I need to get away. I need to get away. It will kill me. What the hell is that?"
Under normal circumstances, Dōma would never do this. Retreat was not in his nature. Fear was something he did not possess.
But Akira's new poison, let's just call it fear toxin, was in full effect.
For someone experiencing fear for the very first time, Dōma had no way to regulate it. His thoughts spiraled. His judgment collapsed; instead of fighting, instead of laughing, instead of playing with his prey.
He ran like a coward.
But someone would not allow him to run.
Just as Dōma tried to flee, a blade pierced straight through his back.
Shinobu's sword struck true, driving deep as she injected him with a massive dose of poison. This time, it was not a subtle compound, nor a silent catalyst.
It was plain, powerful wisteria poison.
His body began to dissolve at once, flesh breaking down as the poison spread. Dōma froze, shock flashing across his face. Under normal circumstances, he would have decomposed this poison almost instantly.
But his mind was no longer normal.
Fear clouded his thoughts. Panic shattered his focus. His body hesitated.
That hesitation was fatal.
In the same instant, Zenitsu, Inosuke, and Kanao struck.
Thunder Breathing flashed. Beast Breathing tore through the air. Flower Breathing cut with perfect precision.
Their blades met at his neck.
And this time, it worked.
Dōma's head separated cleanly from his body. Both began to crumble, disintegrating into ash as the poison finished its work.
Upper Rank Two, Dōma, was defeated.
The cry echoed through the Infinity Castle.
Kasugai crows burst into the air, their voices carrying across the shifting corridors as they announced the victory to every corner of the infinity castle. The news spread like a wave, lifting the spirits of demon slayers everywhere.
Upper Rank Two had fallen.
The tension finally broke.
One by one, they collapsed where they stood. Exhaustion hit all at once, bodies giving in after being pushed beyond their limits. Shinobu in particular sank down heavily, using her Demon Slayer Mark had taken a severe toll on her.
Inosuke threw his arms into the air and roared, "WE BEAT HIM!"
Sure, he wouldn't learn the truth about his mother here, but sometimes, victory mattered more than flashbacks.
Zenitsu, still breathing hard, turned his gaze toward Yoriichi Type Null Alpha. The unit stood motionless now, its systems shut down from the backlash of Overdrive.
"Hey… is it broken?" Zenitsu asked.
Shinobu shook her head. "No. It's just resting. Akira said they'll wake up on their own after a while."
She glanced at the group, then smiled faintly. "So… how about we rest for a bit?"
Everyone nodded.
Shinobu let out a quiet sigh. At last, the weight she had carried for so long began to lift. She lowered her head slightly, her voice barely more than a whisper.
"I finally did it… neechan."
The frozen paradise had fallen at last.