Akaza was strong—truly strong.
Even back during the Mugen Train incident, when he clashed evenly with Rengoku, he had already stood among the most terrifying of the Upper Moons.
And later, in the Infinity Castle, it had taken both the Water Hashira—marked and enhanced—and Tanjiro, who had also awakened both his mark and Transparent World, to finally decapitate him after a grueling, all-out fight.
If now, both Rengoku and Chika could manifest their Demon Slayer Marks and wield awakened Nichirin Blades, she might have smiled confidently and said, "Let's finish him fast."
But that power came at a price.
To manifest the Mark, one's body temperature had to exceed 39°C, heart rate over 200 beats per minute—sustaining a body burning from within.
In return, the body's potential burst open, physical limits shattered, but the cost was clear: a shortened life, a clock stopped at twenty-five.
The mark carved across the skin—both miracle and curse.
Trading life for strength… Chika never wanted the others in the Corps to resort to that.
Her dream was simple—after Muzan's defeat, everyone should live on peacefully, whole and human.
The "original" ending? Too tragic. Too cruel.
Even if they reincarnated, she thought bitterly, without their memories, are they really the same people?
Call her naïve if they wished—Chika didn't care.
"If I don't interfere, then what am I doing here?" she thought.
"Tanjiro and the others will kill Muzan anyway. What, I joined the Corps just to get punched around by demons? I'm not a masochist!"
If she was going to interfere, she'd do it properly—rewrite the ending itself.
The thought steeled her resolve.
Her grip on the crimson-black blade tightened—when suddenly, something within her stirred.
It wasn't pain, nor power—something else entirely.
Akaza's golden eyes narrowed; her aura had shifted.
What is this strange form of energy…?
Chika inhaled deeply, tilting her chin up toward the Upper Moon.
"Rengoku," she said quietly, "I'll go in first. You strike when you see an opening."
Rengoku nodded firmly.
Akaza's Compass Needle meant that Rengoku's blazing aura—normally an advantage—only made him easier to read.
If he couldn't land a clean hit, even a Crimson Blade would mean nothing.
And dawn was still far away.
No escape. No delay. Only battle.
Just as Chika prepared to lunge, Akaza's eyes flared.
With a thunderous crack, his feet shattered the earth—and in the blink of an eye, he was in front of her.
Since Muzan's command had rewritten his perception, Chika was no longer "a woman."
Mercy no longer applied.
"Destructive Death: Annihilation Type!"
The air exploded around his fist.
Chika barely had time to react, swinging her Crimson Blade horizontally to block.
BOOM!
The impact blasted her clean off the ground.
Her body slammed into the side of the Mugen Train, the metal denting under the force.
Her hands trembled around her sword hilt.
He's fast—too fast!
Akaza didn't pause. He ignored Rengoku's incoming strike entirely, rushing straight for her.
His instincts screamed that if the two of them fought together, their blades—those blades—would become truly dangerous.
He had to eliminate her first.
Seeing his intent, Rengoku's eyes narrowed sharply. He stepped forward, his blade erupting in flame.
"Flame Breathing, First Form – Unknowing Fire!"
But Akaza was already reading his motion. His leg lifted high, twisting with lethal precision.
"Destructive Death: Foot Style – Shining Swiftness!"
Flame met light in a violent clash.
Rengoku was kicked backward several meters, boots grinding across the ground, sparks flying.
Akaza's foot slammed back down, and he winced—the pain was sharp, burning.
The Crimson Blade's effect on a body that fought barehanded was brutal.
Every strike he landed risked his own flesh.
He clenched his teeth. "Then I'll just finish one of you first."
Even while partially injured, his power only grew more terrifying.
Energy surged through his body as the very air trembled around him.
Akaza's Blood Demon Art—Destructive Death—was built entirely around "Compass Needle," the art of reading fighting spirit.
From that, he extended branches of flawless technique:
Chaos Type – blinding close-range flurries,
Air Type – long-distance shockwaves,
Foot Type – devastating kicks,
Crush Type – overwhelming physical strikes,
Annihilation Type – total destruction in one blow.
And above them all—his most lethal art.
A strike so fast that even a marked Hashira couldn't fully defend against it.
"Destructive Death: Final Type – Blue Silver Chaotic Afterglow!"
At first, it looked like a single punch.
Then—
Hundreds of air blasts exploded outward in every direction, fanning from his arm like a storm of artillery shells.
Each shockwave carried monstrous force.
Where they struck the train, steel folded like paper, plates denting inward.
The section where Chika had crashed moments before was obliterated in a wave of fire and smoke.
Akaza exhaled slowly, steam rising from his shoulders.
That hadn't been an ordinary 100%. It had been well beyond.
After taking both my Annihilation and Final Type… she can't possibly be alive.
He turned—just in time to dodge Rengoku's blazing slash cutting through the smoke.
Akaza grinned, exhilarated.
Despite the lingering pain in his half-regrown arm, his blood was singing.
The Crimson Blade hindered his regeneration, but not completely.
Already, his lost flesh was crawling back.
"Rengoku," he called out, golden eyes burning,
"it's a pity you won't become a demon… but I'll honor you with my full strength!"
He stepped forward—each movement shaking the ground, every breath heavy with killing intent—
as the battlefield once again ignited with flame and fury.