The aftermath of a battlefield always smells exactly the same, regardless of what universe you happen to be standing in.
It is a suffocating mixture of copper, scorched earth, and the cold, hollow sweat of adrenaline leaving the body.
When the sun fully crested the mountain ridge, burning away the last lingering shadows of the Mugen Train crash site, my borrowed body finally decided it had reached its absolute limit.
The terrifying, explosive high of the Upper Moon’s flesh evaporated from my bloodstream in a matter of seconds.
The jagged black tattoos that had crawled across my skin faded into nothingness.
The unnatural, bulging muscle mass rapidly melted away, returning me to Genya Shinazugawa’s wiry, fragile frame.
The physical backlash was immediate and brutal.
I hit the dirt on my hands and knees, violently dry-heaving.
Every single muscle fiber in my body felt like it had been dipped in acid and pulled through a keyhole.
The System had warned me about temporary cellular instability, but reading a blue warning box and actually feeling your nervous system reboot were two entirely different experiences.
My Iron Stomach rumbled in aggressive protest, working overtime to flush the residual toxicity of Akaza’s blood from my organs before it poisoned me.
Around me, the cleanup crew had arrived.
Dozens of people dressed in black uniforms with cloth masks covering their faces—the Kakushi, the Corps’ dedicated sanitation and logistics brigade—swarmed the wreckage like nervous ants.
They were frantic, shouting orders, triaging the unconscious passengers, and staring in absolute, trembling horror at the bleeding, broken form of the Flame Hashira.
“Careful with his abdomen!” a Kakushi medic screamed, his hands soaked in Kyojuro Rengoku’s blood as they carefully loaded the unconscious man onto a reinforced wooden stretcher.
“The wound is massive!
Pack it with coagulant gauze!
If we lose his pulse on the way down the mountain, Shinobu-sama will kill us all!” I spat a mouthful of bitter saliva into the dirt and forced myself to stand.
My legs were shaking, but I managed to holster the Sun-Spitter and slide the moss-green katana back into its scabbard.
I didn’t offer to help carry the stretcher.
I would probably just drop it.
I limped over to where Tanjiro Kamado was sitting in the dirt.
The kid was a mess.
His stab wound had been bandaged by a frantic Kakushi, but his eyes were completely hollow, staring blankly at the spot where Akaza had fled into the woods.
Inosuke was standing nearby, unusually quiet, his boar mask drooping, while Zenitsu was snoring loudly on a stretcher, completely oblivious to the fact that he had survived a catastrophic derailment.
“He got away,” Tanjiro whispered, his voice cracking with exhaustion and grief.
“He ran from the sun.
We didn’t beat him.” I looked down at the protagonist.
The Will of the World wanted him to experience a profound loss here to fuel his growth.
It wanted Rengoku dead.
I had cheated the script by a matter of three inches, but the emotional gravity of the Upper Moon’s overwhelming power had still crushed the kid’s spirit.
“You’re breathing, and the demon is running,” I said flatly, pulling my tattered purple collar up against the cold morning wind.
“In my book, that’s a win.
Don’t act like a loser when you’re still standing on the battlefield, Kamado.
It disrespects the guy who just bought you a second chance at life.” Tanjiro blinked, looking up at me.
His burgundy eyes wavered, tearing up slightly before he wiped his face with a dirty sleeve and gave a slow, firm nod.
The journey back to the Butterfly Mansion was a blur of exhausting transit and terrible carriage rides.
I slept for most of it, my body slipping into a state of aggressive hibernation to repair the sheer physiological stress of forcing a demonic Blood Demon Art through a human nervous system.
When we finally arrived at the estate, the atmosphere was entirely devoid of its usual chaotic energy.
There were no girls chasing Zenitsu with bamboo sticks.
There was no shouting in the courtyard.
The entire mansion operated in a state of grim, suffocating silence.
Rengoku had been rushed immediately into the intensive care ward.
Shinobu Kocho had vanished behind those sliding paper doors with three of her most skilled medical assistants, and she had not emerged for sixteen hours.
I spent those sixteen hours sitting on the edge of the shaded wooden porch, cleaning the barrels of my shotgun with a rag and a bottle of gun oil.
I didn’t pace.
I didn’t wring my hands.
I just methodically stripped the weapon down, scrubbing the residual iron sand and gunpowder from the firing mechanisms.
It was a grounding exercise.
It kept my mind focused on the cold, hard reality of steel and mechanics, rather than the terrifying memory of demonic energy that had briefly surged through me.
Finally, as the sun began to set, casting long orange shadows across the garden, the doors to the ward slid open.
Shinobu stepped out onto the porch.
Her pristine white medical apron was heavily stained with blood.
Her hair was slightly disheveled, and for the first time since I had met her, the terrifying, serene smile was completely gone from her face.
She looked exhausted, her purple eyes dark and hollow.
Tanjiro, who had been kneeling in the hallway for the entire day despite his own injuries, immediately scrambled to his feet, leaning heavily on his wooden crutch.
“Shinobu-sama!
Is he…
is Rengoku-san…?” Shinobu walked over to a wooden basin and began washing her hands, scrubbing the dried blood from her skin with quiet, methodical intensity.
“He is alive,” she said softly.
Tanjiro let out a massive, shuddering breath, his knees giving out as he slid down the wall, burying his face in his hands as tears of pure relief flooded his face.
Inosuke, sitting nearby, let out a loud, aggressive snort that sounded suspiciously like a sob, crossing his arms and looking away.
I didn’t stop oiling my shotgun.
“What’s the catch, butterfly?” Shinobu stopped scrubbing.
She looked at me over her shoulder, her expression entirely unreadable.
She dried her hands on a towel and turned to face us.
“The physical trauma to his abdomen was catastrophic,” she explained, her voice clinical and detached, a professional mask slamming down over her exhaustion.
“The demon’s arm completely shredded the lower left quadrant of his muscular structure, tearing through his intestinal tract and causing massive internal hemorrhaging.
If he had not maintained his Total Concentration Breathing to instantly seal his own blood vessels, he would have bled to death in the crater.” She paused, looking down at the wooden floorboards.
“However.
The damage to his diaphragm and his spiritual core is irreversible.
The network of localized nerves and the muscular density required to expand the lungs for Flame Breathing have been permanently severed.
Even with the finest medical care in the country…
Kyojuro Rengoku will never swing a sword again.
His body simply cannot sustain the oxygen intake required to fight a demon.” The silence in the hallway was deafening.
Tanjiro stared at her, his tears stopping as the weight of her words settled over him.
Surviving was one thing.
But for a Hashira—a man whose entire identity, philosophy, and purpose were tied to the blade—losing the ability to fight was a fate that bordered on living death.
“He is currently in a deep, medically induced coma to allow his remaining organs to heal,” Shinobu finished quietly.
“He may not wake for months.
When he does…
he will be officially retired from the Demon Slayer Corps.” Tanjiro bowed his head, his fists clenched so tightly on his knees that his knuckles turned white.
He didn’t argue.
He didn’t scream.
He just absorbed the tragic reality of the world they lived in.
I snapped the barrels of the Sun-Spitter shut with a sharp, heavy clack.
The sound made them both jump.
I wiped the excess oil from the oak stock, stood up, and slid the weapon smoothly into the leather holster on my right hip.
“He survived,” I said, my voice cutting through the heavy grief in the air.
“He didn’t surrender, he didn’t become a demon, and he kept his promise.
Nobody died on that train.
That means he won.
Don’t mourn him like he’s dead when he just won the hardest fight of his life.” Shinobu looked at me, a flicker of genuine surprise breaking through her clinical mask.
A soft, tiny smile returned to her lips.
“You have a remarkably blunt way of looking at the world, Genya-kun.” “I just hate crying,” I grunted, turning my back to them and walking toward the edge of the porch.
I stepped down into the gravel of the courtyard, leaving the emotional baggage of the protagonist behind.
I had hit the narrative checkpoint.
The Will of the World was satisfied.
I had earned my keep, but I needed to know exactly what I was working with.
I walked to the far corner of the estate gardens, out of sight of the main ward.
I needed to test the limits of my body.
I stood in front of a thick, ancient oak tree.
I closed my eyes and reached inward, feeling for that well of kinetic energy I had absorbed from Akaza’s flesh.
During the fight, it had felt like a roaring furnace, granting me impossible strength, accelerated regeneration, and the ability to project a crude shockwave.
I pulled my right fist back to my hip, channeling my intent into my knuckles.
I tried to summon that flickering blue light, the Destructive Death aura that had briefly belonged to me.
I threw a straight punch into the empty air, aiming at the trunk of the oak tree ten feet away.
Nothing happened.
There was no blue flash.
There was no shockwave.
My fist just swung through the empty air with the normal, unremarkable force of a human teenager.
I stepped forward and punched the tree trunk directly.
My knuckles bruised, stinging sharply against the rough bark.
I lowered my hand, exhaling a long, slow breath.
So that was the rule.
The Devourer’s Physique was strictly a rented power.
Once my Iron Stomach fully digested the demonic flesh, flushing the cells from my system, every ounce of strength, speed, durability, and Blood Demon Art faded entirely.
I didn’t get to keep a drop of it.
If I wanted Akaza’s shockwaves or Gokaku’s durability, I couldn’t just eat them once and level up.
I had to rip a piece of meat off them and consume it during the battle.
The buffs were entirely temporary.
I was a human baseline that relied on highly volatile, mid-combat consumables.
I rubbed my bruised knuckles, a dry smirk crossing my face.
It was fair.
The universe wasn’t going to hand me permanent godhood just because I chewed on a severed arm.
If I wanted to survive, I had to be smart, pragmatic, and ruthless.
My sword and my shotgun were my foundations; the demons were just temporary ammunition.
“Caw!
Genya Shinazugawa!
Mission!
Caw!” I didn’t even flinch as the massive Kasugai crow plummeted from the sky and landed on a nearby stone lantern.
“Give me a minute,” I muttered, shaking the lingering sting from my hand.
“No minutes!
Demons do not wait!
Caw!
Head South!
A mountain pass!
Travelers are disappearing in the night!
Go!
Go!” the bird shrieked, aggressively flapping its wings.
I adjusted the bandolier across my chest, ensuring the heavy Nichirin shells were securely fastened.
I checked the tie on my moss-green scabbard.
I didn’t need to pack any bags.
I didn’t need to say goodbye to Kamado, or Zenitsu, or the feral pig-boy.
They had their own training arcs to finish, and their own scripts to follow.
I turned my back on the Butterfly Mansion and walked toward the southern gates.
The East Blue was a memory.
The Grand Line was a distant dream.
Right now, there was only the hunt, the harvest, and the Existential Energy I needed to rip a soul out of the afterlife.
I was going to carve my way through every demon in this country, one pound of flesh at a time, u ntil I had enough power to buy Kuina back from the grave.