"The higher being that descended upon your world thousands of years ago… the authority it carried should have been Dreams and Blood."
Eisen paused slightly. Shinobu waited, fully focused, for him to continue.
"When it arrived, it caused a massive impact. The blood of living beings in your world was tainted by that authority and underwent a metamorphosis. It stopped being mere bodily fluid—becoming a bridge, forcibly connecting an individual's inner mental space to the real world."
"A… bridge?"
Shinobu repeated the word. It should have felt the same as when she first heard it, but now that she understood the principle, a chill crawled up her spine.
"Yes."
Eisen nodded and continued.
"More importantly—your world was originally a purely ordinary one, with no supernatural power at all. For lifeforms born into such a world, anything that came into direct contact with the residue of that higher being's power could never control it."
"Without exception, they were completely contaminated."
"And what that contamination looks like… is exactly what you already know."
He listed it calmly, clinically:
"Mania. Bloodlust. Cannibalism. Total madness. And an inability to survive under sunlight."
Shinobu's pupils contracted. Countless horrific scenes surged up in her mind.
"So this is… the truth of demons?"
Her voice trembled almost imperceptibly—not from fear, but from the vertigo of being struck by something too large to process.
Eisen nodded, his gaze passing over her pale face.
"Yes. That is the truth."
"They are warped, deformed products born from higher-level contamination. But even a being that powerful cannot simply trample a complete world at will."
His tone shifted.
"The world itself has countermeasures."
He lifted his eyes toward the night sky, broken into fragments by branches overhead. His voice echoed quietly through the forest.
"The first counterattack… was containment."
Then Eisen's eyes returned to Shinobu, his expression turning complex—almost strange.
"In fact…"
He hesitated as though weighing how to phrase it.
"The island nation you're standing on now—Japan—has already been completely isolated by the world's will."
"It's become a dead zone. A massive prison with only one rule: you can enter, but you can't leave."
"Isolated…?"
Shinobu's heart jolted. The word alone made her skin crawl.
"Yes. Totally."
"An invisible barrier built from the world's rules themselves now separates Japan from the other continents."
"To the outside world, Japan is no longer a normal country or island. It has become a special region—something like a forbidden realm, a mystic domain."
"A sealed island saturated in contamination, cut off from the rest of the world."
Shinobu went still.
She wasn't ignorant of the outside world. Steam engines. Telegraphs. Odd Western imports—everything hinted at a thriving overseas civilization.
She'd never doubted that other nations existed beyond the sea. But she'd also never truly questioned whether anyone could actually leave this land.
Now Eisen's words shattered the edge of her understanding.
She realized, for the first time, that the ground beneath her feet was wrapped in an unbreakable shell.
Eisen didn't give her long to recover.
"That isolation is the world's self-preservation. For thousands of years, the higher being's contamination has been locked inside this small island."
"It didn't just affect individuals—it seeped into the land itself, twisting and reshaping reality."
"Otherwise, how could ordinary humans like the Demon Slayer Corps possess power beyond common sense?"
His gaze swept across Shinobu's slender body—power hidden beneath delicacy—then to the Nichirin blade at her waist.
"You're fundamentally mortal. Your blood isn't special by birth. So how could you, with nothing but will and training, so easily project your mind through breathing and make it real—enough to slay monsters that violate reality?"
"The effects of your Breathing Styles all come from this soil—this land that has been contaminated and mutated. They are byproducts of warped rules."
A cold current shot from Shinobu's feet straight up her spine.
The power she took pride in… the techniques forged through countless deaths, through sweat and blood…
Their roots were a symptom of the world's sickness?
She remembered the days of relentless practice. The comrades who bled beside her. The nights where she forced herself to smile through grief.
All of it… built on a diseased foundation?
Her fingers tightened around the sword hilt. The cold of the handle didn't help—if anything, it made the absurdity sharper.
She drew a slow breath and forced down the surge of emotion. When she spoke, her voice carried a thin, sharpened edge.
"If the contamination has spread across all of Japan, and it's still fermenting… then it can't be only 'benefits.' There has to be a price."
She seized the key point instantly. Power never came without cost—especially contaminated power. Demons themselves proved that by needing to feed.
Eisen nodded as if it were obvious.
"Of course. Honestly, Shinobu—Japan's overall mental state right now is… deeply troubling."
He shook his head slightly.
"Even without comparing it to healthy worlds across the multiverse—just compared to the continents on your own planet that remain untainted and still follow ordinary physics…"
"Your spiritual atmosphere here is profoundly… abnormal."
He began walking through the trees as he listed the signs he'd sensed.
"Widespread repression. A hidden madness. Anger that ignites too easily."
"And a near-pathological fascination with death and decay."
"You call it mono no aware—the cultural core of sorrow for fleeting beauty, a fixation on fading."
"But at a deeper level, that isn't merely 'culture.' It's collective mental distortion shaped by thousands of years of contamination."
"It's an imprint burned into civilization's foundation."
"Madness has been this land's base color for a long time. Only the form changes."
Mono no aware…
The ache for transient beauty. The praise of vanishing.
Shinobu's mind involuntarily summoned her sister Kanae's gentle, slightly sorrowful smile—comrades falling like cherry blossoms in battle—civilians breaking in despair.
Were the emotions carved into her soul… the bonds she had sworn to protect… nothing more than contamination's psychological branding?
Coldness climbed her spine so hard she nearly lost balance.
Shinobu's voice came out bitter, shaking despite her effort.
"Then… how can this possibly be 'good news'?"
"Because it represents possibility."
Eisen's voice rose sharply, his eyes deepening.
"For someone like me, using power in an unfamiliar world depends heavily on compatibility. But there's another way."
He lifted his hand. A tiny flame—First Flame—ignited at his fingertips.
"I can forcibly embed the rules of First Flame into a world's underlying logic."
"If I truly did that, the world would enter an early phase of unimaginable prosperity—a golden age."
"Under First Flame's burning, a world's potential is ignited, catalyzed, forced into bloom."
"Civilization would explode like a supernova—blindingly brilliant—reaching an unprecedented peak."
Then his tone turned cold with inevitability.
"But if you stretch the timeline—thousands, tens of thousands of years—this world would eventually burn into absolute nothingness."
"That brilliance is borrowed from the world's own essence."
Eisen flicked his hand and extinguished the flame, then looked back at Shinobu.
"And that higher being that once visited your world—what it did was similar."
"Not intentionally. It didn't 'gift' you anything."
"It didn't care about your world at all."
"It was simply too vast. Power leaked naturally, without restraint."
"So after thousands of years, your world has been passively strengthened by contamination—its rules warped."
"And that warped soil birthed demons—monsters that shouldn't exist."
"If you let the contamination ferment for thousands or tens of thousands more years…"
"This land could eventually grow a disaster like the Flame of Ruin—but composed of corrupt blood."
"The entire world would rot, sink, and ultimately die in endless filth."
He eased his tone slightly, offering another path.
"Of course, there's also the possibility that the world gradually dilutes and consumes that contamination over time."
"It might fall back into the category of a purely ordinary world."
"But that process would still involve immense pain, uncertainties measured in millennia, and unpredictable variables."
Eisen returned to the present.
"Right now, Shinobu—your world, or rather this sealed Japan—has a power system whose core is projecting one's inner image outward to interfere with reality."
"That is a road with an extremely high ceiling and immense potential."
"You could call it: the larger the heart, the more reality can be twisted."
"In a universe as vast as Kafka's—one that plays on the scale of galaxies—this kind of 'will-made-real' would still earn a place."
He paused, and there was a hint of genuine approval in his voice.
"And your world's countermeasure is very precise."
"It sealed Japan into an absolute information cocoon."
"By cutting off the flow of information in and out, it prevents contaminated, mentally warped individuals from receiving external stimuli that might expand their imagination."
"Someone who has never seen the sea cannot imagine its vastness."
"And the boundary of imagination… is the boundary of how far reality can be bent."
Eisen's gaze locked onto Shinobu, serious and direct.
"So here's my advice."
"What you need most right now is not to keep 'forging yourself' on this sealed, contaminated land."
"You need to leave immediately."
"Go to other group members' worlds. Expand your knowledge. Broaden your eyes."
"Learn different systems. See different kinds of power."
"Everything you witness and learn—turn it into nourishment for your own growth."
Shinobu's brow furrowed. She forced herself to think through the storm in her mind, speaking with confusion.
"But Guildmaster… you said yesterday that different worlds' power systems have severe compatibility limitations."
"Just like you."
Her stomach tightened as she remembered his burned-out body.
"You forced your blood flow too fast, your body ignited, and you became… like a corpse."
"If I try to learn other worlds' power, progress will be slow, and it could even be dangerous."
"And most importantly—if those powers can't be brought back and used in my world… what does the learning actually mean?"
Eisen's mouth curved into a satisfied expression—there it is, the real question.
"You're exactly right. For most systems, other worlds' powers are only references."
He nodded, then pivoted.
"But your world's system—blood as a bridge—is special."
"The foundation of your strength is blood quality and blood flow, connected to will."
"If those two rise high enough, your mind can hammer reality harder through that bridge."
"So when you fight and learn in other worlds—when you become stronger, when your knowledge deepens—even if you can't 'copy' a power system back into your world exactly…"
"Your cognitive boundary will expand."
"And that internal expansion will be compatible with your world's system."
Eisen paused, then delivered the more shocking point.
"And the most absurd rule in your world is this:"
"Your ability—mind influencing reality—also includes the ability to influence blood quality and blood flow themselves."
Shinobu's eyes widened.
Eisen stared straight back at her.
"That means if your will is strong enough…"
"You can literally step on your own foot to climb into the sky."
"Step on… my own foot…?"
Shinobu froze.
"Yes."
Eisen's tone sharpened, laying out the loop.
"Step one: raise blood quality and flow."
"Step two: stronger blood lets your mind influence reality."
"Step three: use that reality-influencing will to act directly on your own blood—command it to become purer, faster."
"Step four: the strengthened blood supports an even stronger mind…"
"Repeat the loop."
"As long as your will can withstand the spiral, you can self-reinforce exponentially."
"In theory…"
"There is no ceiling."
"…It can work like that?!"
Shinobu cried out, stunned.
Her worldview shattered—then reassembled into something both terrifying and intoxicating.
Not disciplined training alone…
But wrestling with rules through sheer will, turning herself into a runaway engine.
It sounded insane.
And yet it perfectly matched everything Eisen had revealed about contamination and warped laws.
Eisen watched her expression—shock, vertigo, and something newly lit behind her eyes—and nodded.
"It can."
"So, Shinobu. Go."
"Go out into other worlds. Eat their knowledge. Expand your horizon."
"When you've seen the scenery of ten thousand worlds, your strength will grow beyond imagination—enough to rewrite the tragedies of your world."
Humans are, in the end, shaped by environment.
Think of Newton—if you dragged him straight out of the seventeenth century into the modern age and shoved an advanced electromagnetism problem into his hands, he'd be completely lost.
Electromagnetism didn't even exist as a field yet. His era limited his cognition. Even a genius can't create knowledge from nothing.
But can you say Newton was "weak"?
He was a giant who dragged the entire mathematics and physics community forward by himself.
Give him a week with modern textbooks and exposure to new ideas—would electromagnetism really stop him?
Of course, the more likely outcome is that he opens the book, sees calculus written entirely in Leibniz notation, and collapses on the spot.
The same applies here.
Japan in Shinobu's world has been saturated for millennia—every person a potential "madman candidate."
But because imagination is locked down, even madness has a ceiling.
So what you get is a nation that becomes obsessive, fanatical, unstable—like animals trapped in a cage.
Then Muzan appeared. He drank medicine made from the Blue Spider Lily, becoming the origin of demons.
The demon plague spread, and humanity's worldview broke open—people learned that life could be twisted into something nonhuman and horrifying.
Power to resist emerged. The Demon Slayer Corps was born.
That was the first evolutionary peak.
The second peak was the world's second counterattack: to eliminate Muzan—the fuse—its own forged ultimate weapon, a child of the gods—
Yoriichi Tsugikuni.
Born with the mark. Born with the Transparent World. Born with a red blade. Born with Sun Breathing.
Yoriichi was born at the summit—an avatar of the world's will.
His legacy—Breathing Styles and forms—showed the Corps how high humans could reach, lifting them to a new peak.
But Yoriichi carried too much contamination within him. His divine nature and humanity clashed, and before meeting Muzan he spent his life wrestling with questions like Who am I? Why do I exist?
As a result, when he finally faced Muzan, he could only unleash fifteen hundred slashes in an instant and still fail to finish him—Muzan escaped, full of "kingly" grace.
Shinobu drew a deep breath, the cold air filling her lungs as she tried to straighten the mess of thoughts inside her.
"To leave the Corps… to leave here… and go learn in other worlds first?"
Her voice was extremely soft—more a question aimed at her own heart than spoken aloud.
Kanae's will. Her comrades' lives. Blood debt against demons.
These weren't burdens she could simply "set down."
Eisen immediately caught the thread of her hesitation and softened his pace.
"As before—when you leave, time in your world will stop completely."
"You don't need to fear that everything will collapse while you're away."
"You don't need to fear demons taking advantage."
"You don't need to fear missing the chance to save someone, or returning to find comrades dead."
"You can go and grow stronger—completely, absolutely without distraction."
Then he dropped the heavy news he'd been holding.
"And I found something else."
"Because the contamination is so deep, this 'demon realm' Japan has already warped into a vast collective dream."
"It contains multiple layers—something like heaven, something like hell."
"Your sister Kanae's consciousness… or her soul…"
"…may currently be wandering somewhere within one of those layers."
Shinobu's body went rigid as if struck by lightning.
Eisen didn't let her breathe.
He met her eyes—eyes suddenly filled with shock and desperate light—and said:
"If you learn the right knowledge in other worlds—methods to pull a soul from the underworld and rebuild flesh…"
"Then reviving your sister will no longer be a hollow fantasy."
"And you know this—under the boost of the Thought Singularity, learning difficulty isn't your real obstacle."
"Revive… my sister…"
Shinobu whispered the words.
This wasn't "rewinding time," that intangible mirage.
Eisen had drawn a path she could walk:
Go. Learn. Gain power beyond common law. Return. Pull her back from the world after death.
After a dead silence, Shinobu lifted her head.
The uncertainty and hesitation were gone—replaced by something sharp, clean, and absolute.
She took a deep breath and spoke without the slightest delay:
"Understood, Guildmaster."
"I will return to Corps headquarters, report everything to the Master, and then depart for other worlds."
Eisen's smile stayed in place, but inside he clicked his tongue in irritation.
Then he spoke lightly, as if it were a simple reminder:
"Shinobu, you understand this, right?"
"When you leave, time stops. But what about the time between now and the moment you actually go?"
"If you delay here for one minute, your world runs for one more minute."
"And in that minute—somewhere you can't see—an innocent person may be found by a demon, torn apart, and eaten."
"The longer you stay, the more people die."
"Conversely, the sooner you depart, the sooner you begin learning, the sooner you gain the power to crush demons."
"And when you return stronger…"
"You prevent those tragedies sooner."
Shinobu's face changed instantly.
"…Understood."
She said it like a blade falling into its sheath.
"Guildmaster—I will leave immediately. Not a second wasted."
A translucent group interface unfolded before her at once.
Then she turned to Eisen.
"Which world is best as my starting point?"
Eisen answered without hesitation.
"Sakiko's world."
Sakiko stepped out of her cheap, rundown apartment building.
She didn't linger on the main street. Instead, she slipped into a narrow alley.
After confirming no one was watching, she stopped.
A translucent chat interface opened in her vision.
Shinobu Kocho's transfer request was flashing.
"Approved."
Sakiko confirmed in a low voice.
In the next moment, Shinobu appeared abruptly before her.
The instant she materialized, she bowed smoothly and elegantly—perfectly formal.
When she lifted her head, her signature gentle smile returned, and she spoke softly:
"Good to see you again, Sakiko."
"Thank you in advance. I'll be relying on you for a while."
"Welcome to my world, Shinobu Kocho."
Sakiko returned the bow with Toyokawa family etiquette, smiling politely.
Guildmaster really moves fast, she thought.
Sakiko wasn't surprised Shinobu chose her world.
Among the many worlds in the group, hers was the most peaceful.
And it wasn't overwhelmingly vast like Kafka's—where stepping outside might mean staring into an entire sea of stars and losing your footing.
More than that, Sakiko felt that Shinobu's current state resembled her own before she joined the group.
Sakiko had clawed her way out of her past shadow by awakening a Persona.
If Shinobu could use tools like that in Sakiko's world—if she could treat her wounds at the root—
Then nothing could be better.
Join here to read ahead.
In Star Rail, Ultra-Beast Armored — Have I Caught "Equilibrium"? l (Chapter 80)
Uma Musume, But I Only Have Five Years Left to Live (Chapter 178)
Zenless Zone Zero: I'm a Doctor, Not a Bangboo (Chapter 155)
Ben Tennyson Wants to Join the Justice League ( 126 )
TYPE-MOON: Redemption Beginning with the Holy Grail War (Chapter110)
Yu-Gi-Oh! — Transmigrated into the White Dragon Girl (Chapter200)
"Is this chat group even serious?" (Chapter110)
I, Lord Ravager, Utterly Loyal! (Chapter230)
Can Playing Games Save the World? 65
Crossover Anime Multiverse: The Demon Hunter of an Unnatural World 77
From Junkman to Wasteland 66
Weekly Refresh of Overpowered 31
I'm Grinding Proficiency Like 46
From Kiana, Lord Ravager, Onwa 200
Honkai: Is This Still the Prev 42
Elf: My Starter Pokémon Is Inc 65
Warhammer: My Primarch Is Remi 180
From Demon Slayer to Grand Ass Volume2/5
The Way the Umamusume Look at 68
Uma Musume, but My Cheat Power 230
Naruto: Weaving the Future, Be 65
Zenless Zone Zero, but Kamen R 76
Multiverse Crossover: The Perf 66
My Cyberpsycho Girlfriend 65
Uma Musume: The Dark Trainer 220
Uma Musume: A Calamity Born fr 154
I, a Reincarnation-Loop Player Volume4/30
The Violent Girl Group Is Beat 120
Uma Musume: The Horse Girl Who 67
Uma Musume: From Beginner 135
Becoming a Horse Girl, I Will 85
Uma Musume: I Want All 110
I Can Copy Unique Skills 100
Summoning an Evil God, but the 70
Supernatural Multiverse 100
My Harem Is Indescribable 90
Jujutsu Kaisen: Heroic Spirit 95
"I'm just a Valkyrie passing through." 68
Uma Musume: Today Is Another Romantic Battlefield 105
Still playing traditional Honk 69
The Most Filial Son Under Heav 80
What Should I Do After Switchi - Volume2/3
Reincarnated as a Demon, Skill 70
Hell-Difficulty Dungeon? 55
Transmigrated as Sukuna 75
Checking In in Demon Slayer 80
The Reincarnating Trainer of Tracen Academy 85
I Refuse to Become a Heroic 70
My Best Friend Into a Slime? 65
A Saiyan Stands Above Marvel 70
What Do You Mean by Using a Lab Mod to Be the Hero? 70
Tanya Starts from Re:Zero 65
Why did they assign me to Uma 65
MYGO Beauties 65
DanMachi: Emiya the Giant Hero 55
The Gacha Merchant Who Started 65
Honkai's Otherworld? Wait—Who Are You People?! 45
Emiya Shirou, Determined to Slay Every Curse and Evil Spirit 45
The Uma Musume Who Became 40
I'm Definitely Not the King of 45
After Maxing Out Every Class 45
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