Since that's the case, then let it never recover!
Whoosh whoosh!
She thrust the Engulfing Lightning in her hand into the soil beside her. With a flick of her slender arm—
Zzzt zzzt!
Musou Isshin materialized from purple light particles, held loosely at her side. The ground beneath the blade's touch crackled and shattered, scattering fragments of distorted space like rippling waves.
"Just now, you kept saying you didn't want to face my blade—turns out demons really are full of lies."
She mocked her opponent.
"I truly didn't want to fight you. But since you refused to join us, I can't let you leave either. I enjoy battling strong opponents. It's not for anything else—self-satisfaction is everything to me."
Crack!
Akaza casually shook his hand, wiped his nose, then spread his legs wide into a firm stance.
Boom!
A heavy sound echoed as the ground beneath him split apart!
His upper body straightened, and he raised his fists into a familiar martial stance.
Whoosh!
Muscles all over his body bulged in an instant, veins popping across his forehead.
"Technique Deployment!"
Hum~
With his shout, a deep violet light appeared beneath his feet, spreading outward in a radius of several meters. The light converged, forming the shape of a snowflake that pulsed rhythmically, glowing brighter and brighter until it was filled with a deep red hue. Around him, both ground and sky shimmered with sharp radiance.
Within the twelve branches of the snowflake pattern, crimson light particles formed the characters from 'One' to 'Twelve'.
Hum~
The formation shifted again, this time glowing with the icy color of frost.
"Destructive Death: Compass Needle!!"
With a roar, his body vanished from sight, charging toward the woman before him!
Boom!
In that instant, he became a blur, his movement dragging a storm of dust around him like a wild beast lunging to devour her.
"If you won't become a demon, then I'll kill you!! Woman!!"
Whoosh!
He appeared before her in a flash, throwing a punch!
She tilted her head slightly—the blow grazed past, brushing against her long hair. The air warped, bursting open a pocket of space the size of a fist.
Whoosh!
She lowered her body and kicked the hilt of Engulfing Lightning up into her hand, spinning it once before slashing toward his fist!
Akaza grinned and met her strike head-on with his bare hand!
Boom!
A dull impact rang out—his fist met the blade with the hardness of steel, locking the edge of her weapon between his knuckles.
So… he's wrapping his energy around his fists to harden them?
"Heh…"
Akaza sneered.
"..."
However—his grin froze a second later.
Zzzt zzzt!
Engulfing Lightning began to glow with blinding violet light. Her entire body surged with electricity strong enough to tear through the air. She twisted the naginata sharply, slicing along the seam of his fist!
Slash!
Even a fist that hard split open under her blade, exposing flesh and bone!
"Wh—?!"
Akaza froze, his arm dropping uselessly. His forearm burst apart like a shredded tentacle—pathetic and grotesque.
A flash of lightning illuminated his stunned face. Before he could react, the Shogun swung again—Engulfing Lightning cleaved straight through his other arm, the lightning-infused cut smooth and effortless.
Boom!
She followed with a powerful kick!
Whoosh!
He was sent flying like a cannonball, dragged across the dirt for dozens of meters before crashing heavily into the ground!
"Destructive Death: Disorder!!"
He recovered almost instantly, changing stances. Air surged wildly around him as he unleashed a furious barrage of punches toward her.
Whoosh! ×N!
Endless shockwaves tore through the air, countless gusts of wind roaring toward her like storm dragons. At first, she blocked with Engulfing Lightning—but quickly decided otherwise.
Zzzt zzzt!
Her body dissolved into lightning, darting between the storm of blows as she shot straight toward him!
"Tch! Destructive Death: Air Type!"
Realizing his attacks were missing completely, Akaza clicked his tongue in frustration and switched forms. With incredible force, he unleashed six punches—their wind pressure thicker and more ferocious than before, like enormous blades of air aimed to consume the oncoming lightning.
"Bury the Thunder!!"
The woman, her form now composed of crackling lightning particles, coiled in the air like a thunder dragon before unleashing a colossal ocean of electricity. The roaring waves of lightning surged tens of meters high, accompanied by an earth-shaking rumble that rolled toward Akaza like a ferocious beast descending from the mountains!
"Wh—What is this technique?! It's stronger than a Blood Demon Art!!"
This wasn't any Breathing Style—no Hashira could possibly possess such overwhelming power! Was this woman… even human?!
Even as such thoughts flashed through his mind, Akaza didn't give up. Instead, he prepared his next move!
"Destructive Death: Annihilation Type!!"
The ground around him shattered, blue energy gathering around his fists. The compressed air thickened rapidly, expanding into massive waves of power several meters wide. He roared and launched himself toward the thunderous tide!
"Take this!!!"
Boom!
The blue energy wave collided head-on with the surging lightning ocean. The clash shook the air itself—Akaza's instincts screamed in terror at the overwhelming force before him.
Annihilation Type wasn't enough?! He could feel searing pain in his arms, his legs trembling as the shock forced him backward. The earth beneath his feet cracked, sinking under the pressure until he nearly fell into a crater of his own making.
"Graaahhhhhh!!!"
He roared, pouring every ounce of strength into resisting the blinding lightning storm—but then—
Hum~
From within the lightning tide, a figure shot forth, appearing right before his face.
"!!"
Akaza's body stiffened instantly, dread crawling up his spine.
Whoosh!
A flash of light—her blade struck at his freshly regenerated arms!
Crack! ×2!
Two violet slashes crossed over his shoulders in the shape of an X!
Slash!
"GAAAAHHHH!!"
Pain exploded through Akaza's body—this wasn't ordinary pain but something far deeper, a searing agony that tore into his very bones. He didn't even understand what had happened—only when he looked up did he see the woman standing before him, her eyes gleaming with cold lightning, her blade poised in an iaijutsu stance.
So fast!!
He couldn't even see her move!
At that moment, true fear crept into his heart. This woman's power far surpassed anything he'd imagined—she was someone who could truly threaten Lord Muzan himself! If even he, Upper Rank Three, was struggling this much, then…!!
Hum~!
Another slash!
"Tch!"
He leapt back desperately, but it was too late—his left leg was severed cleanly.
Thud!
"Urgh!"
He hit the ground hard, tumbling across the dirt in humiliation.
Tap, tap...
The Shogun exhaled softly, lowering Musou Isshin to her side as she stepped toward him with the calm precision of a hunter approaching her prey.
"Damn it!! That speed—no human body could possibly endure that! What are you—?!"
Akaza rasped, his voice hoarse, his body trembling. Even the light surrounding her was unnatural—no Hashira could emit such dangerous power!
"…When," she said coldly as she stopped before his fallen form, "did I ever say I was human?"
"!!"
Her words made Akaza's entire body convulse. Slowly, he lifted his head to look up at her.
Her violet eyes gleamed like judgment itself. Behind her, the Chakra Desiderata began to spin slowly, its divine radiance pressing down upon him like an inescapable nightmare.
"Y-You… impossible!! Impossible!!"
Such a being couldn't exist in this world!
He had always believed that as an Upper Rank demon, he was nearly invincible. But this woman—!!
"I… I can't… be killed by a woman like you!!!"
Thud!
He forced every ounce of power into regenerating his wounds—but—
Nothing happened. The wounds wouldn't heal!
The harder he tried, the greater the pain became. Looking down, he saw that the edges of his wounds were crawling with violet lightning, searing and corroding his flesh.
Why?!
…It's that sword!
Yes—the sword! When had she switched blades?!
She didn't waste her breath on him. Raising Musou Isshin high, she prepared to strike him down once and for all.
"GRAAAHHHH!!"
Seeing her movement, adrenaline flooded Akaza's veins. With sheer desperation, he launched himself several meters away, landing heavily on one foot. Then, dragging his maimed body, he turned and fled toward the eastern horizon, leaping awkwardly but fast—so fast that he practically hopped his way across the ground in a frantic escape.
"..."
Watching the pathetic figure of her opponent fleeing into the distance, the Shogun did not immediately give chase. Instead, she quietly lowered her blade and turned her gaze eastward. On the far horizon beyond the plains, the first rays of dawn were emerging—warm light spilling gently across her face.
Morning had come—
It must have been around five o'clock.
If the battle continued any longer, even if she didn't kill him, the sun would. That was why he ran so desperately.
[...You're letting him go?]
Ei's voice echoed in her mind.
"Of course not."
She shrugged lightly.
[Then what are you doing...?]
Ei couldn't quite grasp her intent. Akaza had already fled nearly a hundred meters away, yet on this flat plain, his figure was still clearly visible.
"I'm waiting for the right moment."
She raised Musou Isshin, adjusting its angle as she tracked his distant silhouette—just as she used to when she traveled with the Traveler.
[Haa… up to mischief again, I see.]
Ei's tone was helpless, though she didn't object. After all, she trusted her daughter's skill more than anyone else.
He was an Upper Rank demon—a heavyweight. Killing him too easily wouldn't do. He deserved a fitting farewell.
She still remembered Musoujin Gorge—and this vast plain was perfect for it.
The moment was right. Dawn had fully broken, and the morning light painted her lavender kimono in hues of ethereal beauty.
Zzzt zzzt—
Violet lightning burst forth from her body, lifting the surrounding dust and pebbles into the air. Currents of electricity coiled around her like serpents of light, flickering in rhythmic harmony. Her purple eyes glowed like stormlight, and her long hair shimmered with arcs of radiant energy.
Ding~ Ding~!
Behind her, the Chakra Desiderata began to spin, its magatama lighting up one by one with a crystalline chime.
Crack.
Raising Musou Isshin high above her head, her cold eyes locked onto the distant figure of the fleeing Upper Rank Three. Her gaze narrowed—predatory, precise.
Hum~
The sword resonated with her intent, the once-pure violet light deepening to a brilliant, dangerous glow. The space around the blade rippled like water, fragments of distorted reality trembling at its edge, as though bracing for an unimaginable release.
The sky itself dimmed, heavy with rolling thunder.
(Inhale)~
She parted her lips slightly, drawing in a breath. Both hands tightened on the hilt—then, in one fluid motion, she brought the blade down in a single, vertical slash!
Whoosh!!
In that instant, time stopped.
Before her eyes, the entire landscape shattered—every inch of space along her line of sight fractured like glass.
Crack!
A shimmering cut cleaved through the world, bisecting the very fabric of reality.
Crash!
The fragments fell away, and time resumed.
BOOM!
A blinding explosion followed. Directly ahead, the earth split open—a canyon thousands of meters long, dozens wide, and equally deep carved into the plains by her strike!
Just as she had calculated, the rift stretched perfectly between both sides of the plain—a seamless divide.
Zzzt!
At its center, violet lightning crackled endlessly, roaring like a living storm. The air above it shimmered with violent energy.
As for its intended target—the Upper Rank Three had been utterly annihilated. Not even ashes remained. He had evaporated from existence, his life snuffed out before he could even comprehend what had happened. Perhaps, in his final moment, his mind still clung to the memory of fleeing.
"Phew…"
She lowered her sword, satisfied as she gazed upon the vast rift before her—Musoujin Gorge.
[Shogun, you overdid it.]
Ei sighed.
"Did I? I think it's just right."
She showed no remorse.
[Haa… this child…]
Ei's voice carried both exasperation and faint amusement. It reminded her of her own recklessness long ago—when her fury had split the land itself and created the first Musoujin Gorge. Was her daughter teasing her now?
[He's dead, isn't he?]
"If he isn't, that would be interesting."
She smirked lightly. Surviving such a strike? Then he wouldn't be a demon—he'd be a god. But no, even gods could die. Only those with divine-level defenses could endure it.
Tap, tap…
"What an outrageous swing that was!"
Footsteps approached from behind. Hearing that familiar voice, she didn't need to turn to know who it was—clearly, he had awakened.
"Not outrageous to me," she replied casually, glancing aside to see the Flame Hashira, Kyojuro Rengoku, arms folded as he stood beside her, gazing at the newly carved canyon.
"Ah, I woke up just now. I saw you cut down that demon—it was Upper Rank Three of the Twelve Kizuki, one of our greatest enemies. Yet you felled him in a single strike. Truly astounding!"
Rengoku Kyojuro praised her with sincere admiration.
"As expected, Kocho was right. Inviting you into the Demon Slayer Corps was the best decision she ever made."
Perhaps if it had been him facing that demon, it would've been a brutal, drawn-out battle.
Click.
He drew his Nichirin Blade, stepping to the canyon's edge to gauge its scale. His golden eyes narrowed slightly, his tone growing serious. Yet even with such shock, his composure remained.
"Such magnificent swordsmanship… pure energy condensed into a cut. A technique born of pure sword aura! This kind of power is beyond any of us. But—this should become a goal for the Demon Slayer Corps to pursue!"
Having a goal was good. Without one, people would become arrogant and self-centered. He was certain—if the others had witnessed this, their jaws would've hit the ground. Even for him, a man of unshakable calm, this display of inhuman strength left him in awe. Indeed, there was always someone greater. The world hid masters in plain sight!
"You flatter me," she replied calmly, folding her arms. "Each swordsman should have their own style. There's no need to imitate mine."
"Mm! Well said!!"
He sheathed his blade with a crisp sound, then turned toward the awakening passengers behind them. Glancing back at her, he spoke with his usual bright energy.
"Let's return. This mission is perfectly complete. Slaying a member of the Twelve Kizuki—that's a great achievement."
"No," she corrected softly. "Two."
"Hm?"
"There was another on the train—Lower Rank One. I killed him as well."
"Oh!! Two demons, then! Remarkable! To think a new recruit could achieve such feats—it's truly extraordinary!"
He laughed heartily, preparing to head back.
"You go on ahead," the Shogun said, watching his back.
"Hm? You're not coming?" he asked.
"No. There are matters at home I need to attend to first."
"I see. If it's family business, then there's no helping it."
"Could you deliver this letter to Shinobu for me?"
The Shogun reached into her kimono and pulled out an already-sealed envelope, handing it to him.
"Of course!" he said energetically, accepting it and tucking it into his uniform. His expression was resolute as ever.
"Then, until we meet again, Flame Hashira."
She turned to leave—but his voice stopped her once more.
"Raiden."
"...?"
She paused but didn't turn back.
"Are you… truly human?" he asked solemnly.
"…I am not human."
Her reply was straightforward.
"?"
He blinked, puzzled.
"But… I have human emotions. A human heart."
Hum~
The air before her split open into a familiar rift in space. Without giving him time to respond, she stepped through it. The moment her figure vanished, the gap sealed itself, leaving no trace behind.
"—Ah!! I see now!! You're a demon!"
After a moment, realization struck him—or so he thought. He struck his palm with a loud laugh, clearly joking, though no one was left to hear it.
...
Meanwhile, at the Demon Slayer Corps headquarters, a messenger crow fluttered joyously through the sky before landing on the hand of Kagaya Ubuyashiki, who was walking slowly through the garden with the help of his twin daughters.
Seeing the crow, both girls halted respectfully.
"Report! The Mugen Train mission has been successfully completed by Raiden and Rengoku!"
The crow's sharp, shrill voice echoed across the courtyard.
"Oh? And the results?" Kagaya asked, intrigued.
"During the mission, two demons were slain—Upper Rank Three and Lower Rank One of the Twelve Kizuki. Both were cut down by Raiden alone! Caw~!!"
The crow flapped its wings excitedly, circling overhead.
"!" ×4
For a moment, everyone present was taken aback—even the ever-serene Kagaya, along with the twin attendants beside him, showed visible surprise. Giyu Tomioka, standing quietly to the side, also looked astonished.
"I see… Truly remarkable, Lady Raiden," Kagaya said at last, a soft, proud smile forming on his face.
To slay not one but two members of the Twelve Kizuki—one of them an Upper Rank—alone… That kind of achievement was unheard of. It was proof that Shinobu's judgment had been entirely correct. Raiden possessed the power to change the course of history.
"Master, shall we prepare a welcoming feast for Lady Raiden?" asked the twin sisters in unison, faint smiles gracing their lips.
"Of course—"
"Caw~ One more thing! Raiden has already left, saying she had personal matters to attend to. She won't be returning to headquarters for now! Caw~!!"
The crow interrupted at just the right moment.
"Hehe… it seems the celebration will have to wait," Kagaya chuckled gently, a fond, indulgent smile on his lips. "When she returns, we'll hold it then."
"Yes, Master," the twins replied together, bowing slightly.
After all—Raiden's place among the Hashira was now certain.
"...What do you think, Giyu?" Kagaya asked, turning to the silent young man beside him.
"…As you say, Master," Giyu replied simply, his calm voice carrying quiet respect.
His thoughts, however, drifted back to the words Shinobu had once spoken to him that night—
[She's important—to me, and to all of us.]
[I believe… she has the power to change everything.]
[She's special. I feel that if we lose her, we'll lose something precious.]
He lifted his gaze toward the distant horizon.
Perhaps… you were right, Shinobu.