"Ma'am, you don't want to wake the children, do you?"
Hayashi looked at Kamado Kie—her face full of fear and vigilance—and quietly took a few steps back.
He was well aware of the strength of this mother.
To protect her children, Kie Kamado once headbutted a wild boar unconscious!
With his own small body, he might not be able to withstand that kind of force.
"Who are you? Why did you suddenly appear in my house?!"
Facing Kie's low, wary voice, Hayashi opened his mouth, but no words came.
He couldn't possibly tell her the truth—that he was just a cosplayer.
At the comic convention, he had been cosplaying as Michikatsu Tsugikuni's twin brother, Yoriichi Tsugikuni, when he suddenly time-traveled into the world of Demon Slayer.
Hayashi's gaze shifted unconsciously to the mirror behind Kie.
Although it was dark outside, the reflection was clear.
Dark red hair, a crimson haori, flame-like markings on his forehead, and sun-patterned Hanafuda earrings swaying from his ears.
At his waist hung the sword he had only meant as a cosplay prop.
That's right. He was still dressed as Yoriichi Tsugikuni.
But now, standing in the Kamado household, no explanation could possibly make Kie believe he had no ill intent.
All he could do was force a bitter smile and say, "Madam, I can't explain why I appeared here… but I swear I'm not a bad person. Please, don't be afraid—I'll leave right away."
Noticing her wary gaze fixed on the blade at his hip, Hayashi quickly tried to ease her fears.
"Look, my sword is actually just wood—"
He drew it partway, only to freeze.
The heavy weight in his hand, the razor-sharp glint of steel… this was no wooden prop.
"What?! This was supposed to be fake!"
As the sword cleared its sheath, faint text shimmered before his eyes:
[Yoriichi Tsugikuni's Sword · Replica]
[Grants partial Breath of the Sun resonance when wielded]
[Can merge with Tsugikuni Yoriichi's blade to unlock the true Crimson Red Nichirin effect]
Hayashi's breath caught. He scratched at his hair in disbelief—only to find strands of crimson fall into his palm. His fingers rubbed across his forehead, but no paint smeared off.
His cosplay makeup, his wig, even the fake sword—everything had become real.
More text appeared, glowing faintly before his eyes:
[Current COS Character: Tsugikuni Yuichiro]
[Restoration: 10% — Partial mastery of Yuichiro's abilities unlocked]
A system… that turned cosplay into reality?!
If he reached 100%, wouldn't he truly become the legendary Tsugikuni?
Hayashi's mind raced, but Kie Kamado's sharp voice broke through:
"Please leave! Now!"
She lowered her body, ready to charge. To her, his drawn sword and muttering only meant one thing: a dangerous lunatic had invaded her home.
"I'm leaving," Hayashi murmured quickly, backing toward the door with both hands raised.
But when he slid the door open—his eyes locked with a pale, elegant man in a black suit and white top hat.
That face. That aura.
Muzan Kibutsuji.
At that moment, Hayashi had only one thought:
What the hell?!
…
Muzan Kibutsuji walked along the narrow path of Mount Kumotori.
The deep snow would have made it difficult for an ordinary human to take even a few steps, but to the Ghost King, it was nothing.
He glanced sideways at a small wooden house buried under the snow and muttered coldly:
"An old man… and a child.
Tch, how dull."
For lesser demons, such prey would have been a rare feast.
But Muzan Kibutsuji had long since grown past the thrill of merely devouring humans.
What he desired was not meat, but results—experiments.
For a thousand years, he had searched in vain for the Blue Spider Lily, the key to overcoming the sun.
In his obsession, he had changed his methods. He no longer waited for nature to reveal its secret—he sought to create it.
He granted his blood to humans, hoping one among them would evolve into a being immune to sunlight. If such a miracle occurred, Muzan would simply devour that demon and claim perfection for himself.
But humans were fragile.
The vast majority who received his blood collapsed into twisted lumps of flesh, unable to endure the overwhelming power.
As he walked, Muzan suddenly lifted his gaze toward the summit.
From there, he felt a surge of life—brimming, vivid, unlike any ordinary family. His lips curved slightly.
"Five children… and a woman.
Hmph. One last experiment, then."
But just as he moved closer, Muzan froze.
A faint but unmistakable aura pricked at his senses—an aura sharpened by the art of Breathing Techniques.
His face twisted with annoyance.
"A Demon Slayer Corps swordsman…?
Hah. Another self-righteous fool. Interesting material for my experiments."
Though the Corps were a threat to common demons, to Muzan, they were nothing but disposable test subjects.
Yet at that thought, a violent pulse of rage surged inside him. Blue veins bulged on his pale forehead as a memory clawed its way to the surface.
That man.
That name.
Tsugikuni Yoriichi.
The only human who had ever brought him to the brink of death—forcing him, the so-called perfect being, into fleeing in shame.
Grinding his teeth, Muzan resumed his steps toward the house, muttering venomously:
"Originally, I would have used you as material…
But since you've dredged up his shadow, I'll make sure to torture you until nothing remains.
Ah, but the children… I mustn't let them witness such horrors. That would spoil my fun.
Perhaps I should kill them first."
His lips curved into a twisted smile. He pictured the swordsman's despair, powerless to stop the slaughter.
But then—
The door creaked open.
Muzan lifted his gaze… and froze.
Long, flowing crimson hair spilled into the cold air.
Upon the forehead, dark red Sun Marks burned like brands of fate.
For an instant, Muzan forgot to breathe. His pupils trembled violently.
Hair like flames… markings of the chosen…
And then, glinting in the firelight—Hanafuda earrings.
Every organ inside him clenched in unison. His seven hearts stilled, and all five brains screamed the same thought:
"Impossible! Not again—!!"
It was the same face burned into his nightmares.
The face of the man he could never kill.
The face of Tsugikuni Yoriichi.