"So what you're saying is… if I destroy this train, you'll die completely, correct?"
"Destroy it? Hahaha~! Go ahead and try, little girl! Don't forget—this train isn't just you! There are over two hundred passengers aboard, all my precious food. If you can bear to kill them, then by all means—do it!"
He laughed mockingly at her.
"Heh… Ei, did you hear that?"
She smiled faintly, speaking just loudly enough for the demon to hear, her tone calm and deliberate.
[Heard it. Shall we begin?]
Inside the train, Ei already stood poised, violet energy swirling in her palm—ready to act.
"Hm?"
Enmu's smirk faltered for a split second, confused by her cryptic words.
"If you're so confident, then let's see… whether you're faster—
—Or we are."
Her amethyst eyes glinted coldly as she stared at the grotesque demon head, her lips curling into a faint, taunting smile.
…We?
Enmu's thoughts stalled. We? What did she mean? There were only two Demon Slayers aboard, weren't there?!
"Ei, begin."
Her voice rang clear.
Hum~
In the next instant, blinding violet light engulfed the entire train, swirling like a vortex that drew everything inward. The surrounding space fractured, cracks spreading through the air like shattered glass.
Inside the train, Ei tossed a glowing Eye of Electro into the air. The eye began to spin rapidly, discharging arcs of lightning that rippled through the void like pebbles disturbing a still pond. Each wave caused space itself to shatter, revealing the black void beneath.
The expanding rift spread across the entire train—not to consume it, but to envelop everyone aboard, including the still-sleeping Flame Hashira. One by one, every passenger vanished, drawn into her Plane of Euthymia.
When the light faded, only an empty, silent train remained.
Enmu blinked in confusion, his mind blank. The train was still intact, still racing down the tracks—but his food… was gone. Every passenger—vanished. The cars were utterly empty.
"What… what happened?! What did you—?!"
Panic finally set in. His voice cracked with rage and disbelief. Looking ahead, he realized the purple-haired woman was gone as well.
"?!"
He quickly spread his awareness through the train, merging deeper into its body, searching every car—but there was nothing. Not a single presence remained. It was as if he were utterly alone.
Where did she go?!
He didn't realize that death was already closing in.
Far ahead, the Shogun—now pure lightning—descended from the skies, landing gracefully on the tracks several hundred meters ahead of the speeding train.
The faint rumble of the rails grew louder as she stood still, waiting.
Woooo~!
The shrill whistle of the train echoed through the air. The blinding headlight and billowing smoke loomed closer, the ground trembling beneath her feet.
[Shogun, all passengers have been transferred to the Plane of Euthymia. You can attack freely.]
Ei's calm voice resonated within her mind.
The Shogun's expression hardened. Behind her, the Chakra Desiderata began to spin slowly as the train closed the final distance.
"…No way—!!"
Enmu's horrified voice erupted from within the train the moment he noticed her standing dead center on the tracks.
Too late.
Crack!
Time slowed. The world faded into monochrome, like a black-and-white film.
Secret Art: Musou Shinsetsu!
The blade of Musou Isshin, wreathed in lightning, sprang from her chest as she drew it forth. Her right hand crossed before her body, gripping the hilt; her left steadied it, pulling it free in one fluid, vertical motion.
The brilliance of a thousand bolts illuminated the dark plain.
The blade's light resonated with her eyes, reflecting the cold, divine radiance of the stars.
"Eternity incarnate!"
Her voice rang like thunder as she slashed vertically downward.
Hum~
A searing line of violet light erupted, cutting straight through the massive train before her as if through air.
Crack!
The violent arc of her blade cleaved through everything before her—the tracks, the locomotive, every car behind it. The entire train split cleanly down the middle, each half sliding past her on either side. The exposed cross-sections were not machinery, but grotesque, fleshy growths—pulsing with life. Just as Enmu had claimed, his body had fused completely with the train. Those were his organs… even his heart.
The Shogun stood perfectly still at the center, the two halves of the train roaring past her without so much as brushing against her. The geyser of blood that followed splattered harmlessly against her barrier.
"AAAAAHHHHH!!"
Enmu's piercing scream echoed through the night.
BOOM!!
The bisected train derailed, its halves writhing grotesquely on the ground like a dying centipede before finally going still.
BOOM!
A final explosion tore through the wreckage, flames erupting skyward, painting the distant horizon in blazing orange.
"…Why? Why am I… Lord Muzan… I—"
All that remained of Enmu was a single twitching mass of flesh. There was no fury in his eyes now—only blank despair and confusion. His voice was faint, barely coherent.
Puchi!
The Shogun approached silently and drove Musou Isshin down, slicing him—and the remains of the train—into fine dust. Both disintegrated, vanishing completely from the world.
Tap, tap...
Alone on the open plain, the Shogun flicked her blade once more, scattering the remaining blood. The sky, briefly illuminated by firelight, returned to the darkness of night. Dawn was still far off—it was only around three in the morning.
The vast plain was eerily quiet. No animals stirred, no sound disturbed the stillness. Only the distant mountain silhouettes and the cold, desolate moonlight kept her company.
Hum~
A wave of violet light rippled outward from her. As it faded, the scene before her shifted—hundreds of passengers lay sleeping peacefully on the grass. Among them was the Flame Hashira, still deep in slumber. They would awaken with the sunrise.
Pat...
A light pinch on her arm—no need to guess who it was.
"What about them?"
Emerging from the Plane of Euthymia, Ei glanced at the peacefully sleeping passengers, her tone mildly troubled.
"Let them sleep. They'll wake with the morning. Sleeping on the ground for a few hours won't kill them."
The Shogun folded her arms, gazing idly at the slumbering crowd.
"And you? Are you tired?"
Ei's eyes softened with concern.
"I've disabled my sleep function."
The Shogun answered quietly, eyes half-closed.
"Because of that demon?"
Ei didn't doubt her—she merely asked.
"Correct."
The reply was simple.
"Then make sure to turn it back on later."
"No."
Her refusal was immediate.
"…."
Ei narrowed her eyes slightly, a faint pout forming.
"…We'll… talk about it later."
The Shogun averted her gaze, tone softening.
"Hmph…"
Ei sighed, deciding to let it go—for now.
"Ei, once this incident is over… let's go back."
The Shogun lifted her gaze toward the moon as she spoke softly.
"Hmm? Back where?"
Ei tilted her head in slight confusion.
"…Where else? Back to Teyvat, of course."
The Shogun shot her an exasperated look.
"Are you homesick?"
Ei gently brushed a strand of her daughter's long hair, her touch filled with warmth.
"Maybe a little… but not entirely. I was just wondering—does time here flow the same as it does in Inazuma?"
She allowed her mother's touch without resistance, her voice quiet but thoughtful.
"You're right. We've already been here for a year… but in Inazuma…"
She trailed off, recalling the strange discrepancy in time they'd once experienced. Seven days in another world—yet less than a day had passed in Inazuma. Perhaps even only seconds.
"…Could it be the power of Musou Isshin?"
Ei murmured.
"Musou Isshin?"
She looked up, curious.
"Yes. There are two possibilities. One—time simply flows differently between worlds. But the second, and more likely one… is that Musou Isshin sends us back to the exact moment we departed. Even if a year has passed here, we'll return to the same point in time there."
Of course, it was only her theory—but neither of them could deny the possibility.
"..."
Ei stared at her in quiet thought. Come to think of it… Musou Isshin had once been her sister's companion weapon, yet even now, she had never truly understood its full power.
In truth—if she were being honest—she had never fully understood her elder sister's strength either. Raiden Makoto had always presented herself as a stateswoman, never a warrior. She had never taken up her blade to kill, and that was precisely why Musou Isshin had never been unsheathed. Because of that, Ei had never once witnessed her sister's true might. And so, the sword—and the power it carried—remained a mystery.
Of course, she wasn't referring to combat strength, but rather the unique, inherent ability that belonged to her sister alone.
"Ei?"
The Shogun's voice broke through her thoughts.
"It's nothing… I was just thinking of my sister."
She replied softly.
"..."
Hearing that, the Shogun lowered her eyes in silence.
"Returning sounds good. Besides… I have some matters that need my attention. If an entire year truly has passed, that would be troublesome."
Ei nodded in agreement.
No good—thinking about it that way only made her realize how careless she'd become. She had gotten far too comfortable over the past year, spending her days alongside the Shogun, so much so that she'd nearly forgotten her responsibilities.
"By the way… how long do you plan on eavesdropping?"
The Shogun suddenly crossed her arms and spoke toward the empty plains around them, her tone sharp yet casual.
"?"
Ei blinked in confusion, but then she, too, sensed it—a faint presence lurking nearby, observing them without making a move.
"..."
Silence. Whoever was there clearly had no intention of revealing themselves.
"I don't repeat myself."
Zzzt!
Lightning flared in her hand as she summoned Engulfing Lightning and hurled a massive arc of energy toward the distant horizon. The blade's light sliced through the ground like a shark's fin cutting the sea, crashing down on the hidden presence.
BOOM!
The earth erupted with a thunderous roar, streaks of lightning igniting the soil in a blazing explosion that briefly illuminated the sky.
"!!"
A figure leapt out of the smoke, landing several meters away. As the haze cleared, his true form emerged.
He was a man—short, spiked crimson hair, golden eyes, pale skin etched with countless blue markings. His outfit was a sleeveless maroon haori, and beaded anklets jingled faintly with his movements.
Another demon. Proof of it lay in his eyes—both bearing the characters for Upper Rank Three.
Hum~
Ei's form dissolved into light and merged into the Shogun's body.
"!"
The sudden display made the demon's golden eyes widen slightly—not out of fear, but fascination. The sheer energy of that earlier attack had already impressed him. For a human to possess strength rivaling that of the Upper Moons—it thrilled him.
"That power just now… it wasn't Breathing Style, was it?"
The demon asked, his brow furrowed in intrigue.
"Can't you tell? Why bother asking?"
Her voice dripped with both disdain and disinterest.
"You're with that Flame Hashira over there, right? So you're Demon Slayers?"
"…And if we are?"
She asked coolly.
"Heh… quite the attitude. I like it."
A wild grin spread across his face.
"That strike just now… magnificent. Even I was impressed."
He praised her sincerely, though his grin only grew more feral.
"So what, you want to test it for yourself?"
She asked with a casual lift of her arm.
"Not exactly. I came here to talk—to you… or perhaps, you both."
He hinted knowingly, referring to Ei within her.
"…You're mistaken. There's only me here. No one else."
She corrected him calmly.
"Hehe, no matter. Allow me to introduce myself properly. I am Akaza, Upper Rank Three of the Twelve Kizuki."
He struck his chest with a grin, his tone almost polite.
"Demon Slayer Corps, Thunder Hashira—Raiden Shogun."
Out of courtesy, she replied in kind.
"Heh. Demon Slayer Corps, huh? Such a pitiful, weak organization. Hardly worthy of someone like you. Those others you protect—they're all weaklings."
Akaza's mocking tone carried a twisted conviction. The Shogun could only roll her eyes internally at his self-righteous arrogance.
"So you came all this way just to tell me that?"
She asked dryly.
"Of course not. Let me be blunt—"
He grinned, eyes gleaming with hunger.
"I want to ask if you'd consider… becoming a demon."
Akaza extended his hand toward her, making an inviting gesture.
Why did this kind of ridiculous proposition always come up? She sighed inwardly.
"The last one who said that ended up as dust."
She quipped dryly.
"Hmph, that weakling Enmu had no right to make such an offer. But me—I'm serious. Join us. You carry an aura that commands respect, strength that surpasses any Hashira several times over. You could stand shoulder to shoulder with us, the Upper Rank!"
Akaza's excitement began to rise, his tone brimming with enthusiasm.
"And right now, you're still in a human body. If you became a demon, freed from mortal limits, you would become even more—!"
"No need. This vessel has no interest."
She interrupted his endless pitch with a flat refusal, turning away in disinterest as she prepared to leave. But, of course, he wasn't about to let her walk away so easily.
"!"
Akaza's expression darkened, his golden eyes narrowing as his aura thickened. The pressure of his killing intent cracked the ground beneath his feet.
Boom!
In the blink of an eye, his form vanished. He dashed forward with blinding speed, appearing behind her with a powerful strike aimed at her back.
Whoosh!
The air exploded as his fist tore through it, kicking up a wave of dust and debris.
"..."
She didn't even look back. Her eyes half-lidded, she tilted her head slightly to the side—
Whoosh!
—And effortlessly dodged the blow. His fist brushed past her cheek, the impact creating a gust strong enough to lift strands of her hair. The shockwave carved a long trench into the ground beyond them.
"!"
Akaza's eyes widened in disbelief.
What?! That reaction speed…! He had thrown that punch at near supersonic velocity—yet she had avoided it as though it were nothing! Impossible!
Frustration flashed in his gaze as he clenched his teeth.
He launched another barrage.
Whoosh!
Once again, she slipped aside easily, her movements light, fluid—almost lazy.
"Damn it!!"
Akaza's expression hardened. His fists blurred, striking faster and faster, dozens of punches in mere seconds, all aimed toward her blind spots.
"Haah…"
Turning calmly to face him, she let out a bored sigh. To her, his frenzied assault looked almost like a slow-motion performance. She weaved between his blows with effortless grace, not a single punch even grazing the hem of her sleeve.
She tilted her head back slightly, avoiding an oncoming hook, and in the same motion, gripped her naginata—Engulfing Lightning.
With a single spin, she brought it down vertically toward his right arm.
A streak of violet light flashed, accompanied by the crackle of thunder. The blade cleaved through his limb cleanly.
Crack!
"!"
Akaza didn't even realize what had happened until he saw his arm flying away. Shock overtook his face—his mouth hung open as his severed limb hit the ground.
Whoosh!
He instinctively leapt backward, widening the distance between them. Blood poured from the stump of his arm—but it didn't last long.
Hiss!
In the next moment, flesh and muscle writhed, reforming rapidly until his arm was whole again. The regeneration was instantaneous—far beyond that of lower demons.
She watched him grow his arm back, her face unreadable.
So his recovery rate has improved, huh?
Well, that's to be expected from an Upper Rank.
In that case—she'd just have to make sure he didn't get the chance to heal again.