The transition between universes was not a gentle, ethereal experience.
It felt like being shoved through a meat grinder and spat out into a freezing snow-globe that smelled strongly of rotting meat and aggressively floral perfume.
I hit the ground boots-first, sliding across a thin layer of frost and dead leaves.
My immediate instinct, honed by years of paranoia and brutal training, was to reach for my left hip.
My hand slapped against a coarse, purple fabric.
Empty.
My heart skipped a beat.
I slapped my right hip.
Also empty.
I looked down at myself in the gloom.
The heavy, blood-soaked green haramaki was gone.
Instead, I was wearing a dark purple sleeveless yukata over a black shirt.
I touched my head.
The sides were shaved close to the scalp, leaving a spiky, unruly mohawk on top.
It wasn’t moss-green anymore.
But the hair wasn’t the problem.
“Where is it?” I snarled, frantically patting down the unfamiliar clothes.
“Where is the Wado Ichimonji?!” A crisp, metallic chime echoed in my head, completely different from the bouncy pop-ups of the East Blue.
A sleek, minimalist red interface appeared in my field of vision.
**[Notice: Host inventory has been synchronized with the parameters of Simulation #1: Demon Slayer.]** **[External Artifact: ‘Wado Ichimonji’ has been temporarily confiscated.]** **[Reason: External extra items possess a structural density incompatible with the local reality.
Bringing an indestructible sword into a fragile simulation violates the terms of the wager.]** **[The item is safely stored in the System Vault.
It will be returned upon simulation completion or Host expiration.]** “You stole my sword,” I growled, my hands balling into fists.
“I agreed to survive your simulation.
I didn’t agree to get mugged by a glowing screen!” **[Host is provided with the standard equipment required for this narrative checkpoint.
Please check your right hand.]** I looked down.
Clutched in my right grip was a standard, mass-produced katana.
The blade was a dull steel color, the tsuba a plain black circle.
It was incredibly light.
Too light.
It felt like a toy compared to the heavy, unsharpened practice blades I had dragged through the mud in Shimotsuki Village.
I gave the sword a test swing.
The balance was decent, but my body felt…
wrong.
The insane, tank-like muscle mass I had built up over seven years was gone.
I was still muscular for a teenager—wiry, lean, and tall—but the raw, overwhelming density was missing.
The System had nerfed my base stats to fit the vessel I was inhabiting.
I took a deep breath, trying to calm the sudden spike of panic.
*Focus.
You accepted the wager.
You need Existential Energy to save her.
If the System wants you to use a toy sword, you’ll beat the universe to death with a toy sword.* I took stock of my surroundings.
I was standing in a dense, oppressive forest.
The trees were massive, their canopies blocking out whatever moonlight existed.
Surrounding the base of the mountain, illuminating the dark woods with a surreal, bioluminescent purple glow, were thousands of Wisteria trees in full bloom.
My past-life memories clicked into place.
Wisteria flowers.
A dark mountain.
A test of survival.
Mt.
Fujikasane.
The Final Selection.
I had been transmigrated right into the middle of the Demon Slayer Corps’ entrance exam.
The objective was simple: survive for seven days on a mountain crawling with starved, man-eating demons.
“Alright,” I muttered, rolling my shoulders.
“Seven days of camping.
I can do that.
I just need to find a nice, secluded cave and take a nap.” A twig snapped behind me.
“A nap?” a raspy, gurgling voice echoed from the shadows.
“Oh, you can sleep forever, little morsel.” I didn’t turn around immediately.
I just let out a long, exhausted sigh.
“I literally just got here.
Can I have five minutes to stretch?
My hamstrings feel completely different.” A figure dropped from the canopy, landing heavily on the frost-covered ground a few yards away.
It was a demon.
Its skin was the color of bruised eggplant, and it had three eyes arranged vertically on its forehead.
Its fingernails were elongated into sharp, dirty talons, and a thick string of drool hung from its jagged teeth.
“You look crunchy,” the demon giggled, its joints popping sickeningly as it crouched low to the ground.
“The last kid I ate had a sword like that.
It didn’t help him.
I’m going to peel your face off!” The demon lunged, covering the distance between us in a fraction of a second.
It was fast—much faster than the mountain bandits in the East Blue.
I relied on pure muscle memory.
I dropped my center of gravity, gripping the standard Nichirin sword with both hands.
In this universe, swordsmen relied on ‘Breathing Styles’—specialized breathing techniques that temporarily boosted human physical capabilities to match demons.
I remembered the anime.
You just had to breathe really hard, right?
I sucked in a massive gulp of air, puffing my chest out until it hurt, and swung the sword upward in a harsh, vertical arc.
*”Water Breathing!
First Form!”* I yelled.
My sword met the demon’s descending claws.
Sparks flew.
No majestic water dragon appeared.
No elegant, crashing waves materialized from the blade.
Nothing happened at all, except that I nearly choked on the freezing mountain air, and the sheer kinetic force of the demon’s strike sent me skidding backward through the dirt.
My back slammed into the trunk of a tree.
I coughed, dropping my guard for a split second.
**[Notice: The Host vessel (Genya Shinazugawa) possesses zero aptitude for Breathing Styles.
You cannot generate elemental effects or utilize standard Breathing rhythms.]** “You could have mentioned that *before* I tried to shout an attack name!” I yelled at the air, incredibly embarrassed.
“Talking to yourself, crazy kid?” the demon cackled, leaping into the air again.
“Die!” If I couldn’t use magic breathing, I was just going to have to do this the old-fashioned way.
I didn’t need water dragons.
I was Roronoa Zoro.
I dodged sideways, letting the demon’s claws gouge a massive chunk of wood out of the tree trunk.
The nerfed body was slower, but my battle instincts were sharp.
As the demon’s arm extended, I pivoted, bringing my single sword around in a tight, horizontal slash aimed directly at its neck.
*Ittoryu (Single Sword Style): Thirty-Six Pound Cannon!* Without the massive muscle density of my original body, the flying slash didn’t materialize.
The blade just bit deeply into the demon’s neck.
It hit the bone and stopped, vibrating violently in my hands.
The steel of the standard Nichirin blade wasn’t sharp enough, and I didn’t have the leverage.
“Too shallow!” the demon laughed, twisting its body.
It swung its free hand, slamming a heavy backhand directly into my ribs.
The impact was brutal.
Without my East Blue ‘Iron Defense’, I felt a rib fracture instantly.
I was thrown to the ground, my sword tumbling out of my grip.
I rolled, gasping for air, and tasted blood in my mouth.
The demon stood over me, raising its talons for a killing blow.
“Any last words, snack?” I glared up at the three-eyed freak.
My body was broken, my cheat-code swords were gone, and I couldn’t use the magic of this world.
I couldn’t just stand there and tank hits like a juggernaut anymore.
This body was fragile.
*Fine,* I thought, pushing myself up and grabbing the hilt of my dropped sword.
*If I can’t overpower them, I’ll out-skill them.* I closed my eyes for a fraction of a second, tuning out the pain in my ribs.
I fell into a stance that had nothing to do with magic breathing.
It was pure, distilled biomechanics.
I adjusted my grip, finding the exact center of balance on the cheap Nichirin sword.
The demon brought its claws down.
I didn’t block.
Blocking was a waste of kinetic energy.
Instead, I stepped *inside* the demon’s guard, brushing past the descending claws with a millimeter to spare.
My movement was completely devoid of wasted motion.
The demon’s eyes widened in confusion as it missed its target completely.
It was wide open.
I didn’t swing with just my arms.
I used the rotation of my hips, the pivot of my heel, and the torque of my shoulders, channeling every ounce of this vessel’s physical strength into a single, flawless point of leverage.
*Ittoryu: Lion’s Song.* The blade didn’t just chop; it slid.
I aligned the edge of the cheap steel perfectly with the gap between the demon’s cervical vertebrae.
There was no resistance this time.
The dull Nichirin blade sheared through the demon’s tough neck with surgical precision.
I followed through with the swing, ending in a low crouch behind the demon.
For a second, there was only the sound of the freezing mountain wind.
Then, the demon’s head slid off its shoulders and hit the dirt with a dull thud.
Its three eyes stared wildly as its body slowly began to disintegrate into ash.
I stood up slowly, sheathing the sword with a sharp *click*.
I was breathing heavily, my rib throbbing with a sharp, piercing ache.
“I have to actually dodge now,” I muttered to myself, rubbing my side.
“This is going to be exhausting.” My stomach let out a loud, thunderous rumble.
My ‘Iron Stomach’ was demanding fuel to heal my fractured rib, but my inventory of salted meat was back in the East Blue.
I looked down at the pile of demon ash, my stomach churning with genuine hunger.
“Gross,” I mumbled, turning away from the ash pile.
“I’m not that desperate yet.” Suddenly, a loud crash echoed through the woods a few hundred yards to my right.
Through the dense trees, I caught a glimpse of movement.
A massive, horrifying demon composed entirely of tangled, green hands was smashing its way through the forest.
And dodging desperately between those massive hands was a boy in a checkered haori, wielding a black sword.
He had a scar on his forehead, and he was currently shouting something about a “Water Wheel.” I recognized him instantly.
Tanjiro Kamado.
The protagonist of this simulation.
I rolled my shoulders, ignoring the pain in my chest, and cracked my neck.
“Alright, System,” I sighed, drawing my sword again and walking toward the sounds of the battle.
“Let’s see how much I can break your plot without any magic tricks.” — CREATORS’ THOUGHTS Typing_In_My_Sleep Author_Note Wipes a sleepy tear and adjusts my blanket…
Typing_In_My_Sleep here.
Before I crawl back into bed, I just wanted to take a quick moment to say a massive thank you.
Thank you so much for giving this story your time, your patience, and your reads—it genuinely means the world to me.
Being a total beginner on this app has been a wild ride, so please continue to support this sleepy newbie as I try to figure things out without hitting the wrong buttons.
Alright, my bed is calling me louder than ever.
See you in the next chapter!