Rokuro, Lower Rank Two, was in his hideout admiring the moonlight when he looked at the arm that had yet to fully regenerate, his heart filled with endless frustration.
What the hell was wrong with that brat... Why did a single slash from him completely halt my flesh's regeneration? Even after so many days, I still haven't fully recovered...
He wasn't the type who enjoyed fighting, and he didn't know much about the Demon Slayer Corps. Still, he had heard rumors that among them there existed an origin breathing style capable of dealing tremendous damage to demons.
But hadn't the inheritors of that breathing style already been wiped out by that Lord?
And no matter how he looked at it, that brat used Wind Breathing, just like that woman. So how could he...
Thrum—
The sound of a biwa rang out.
Rokuro suddenly felt the ground vanish beneath his feet, and his entire body plunged downward!
At the same time, three other demons heard the sound of the biwa.
Lower Rank Three, Wakuraba, was wandering aimlessly through the mountains, delighting in torturing lost travelers, when the ethereal sound drew his attention.
Lower Rank Six, Kamanue, had been arranging decorations in his home when, upon hearing the biwa, he was abruptly dragged into an unknown space by an unseen force.
And there was one more—Lower Rank One, Enmu.
He was far more relaxed, standing before a mirror admiring the tattoos on his face, a sickly satisfied smile curling at his lips.
When the biwa sounded, he showed no surprise at all. Calmly spreading his arms, he allowed himself to fall through the floor.
Thud! Thud! Thud!
Moments later, aside from Enmu—who maintained his elegance and fervor as he landed smoothly—the other three demons were unceremoniously thrown onto a flat tatami floor, crashing down in disarray.
They scrambled to their feet almost immediately, panic and confusion filling their eyes as they surveyed this bizarre domain.
The Infinity Castle.
A nightmare space that completely overturned the laws of physics.
Massive, ancient wooden structures intertwined layer upon layer. Countless corridors, towers, sliding doors, and beams overlapped at impossible angles, some hanging upside down in midair, forming a vast and chaotic labyrinth.
Gravity held no meaning here. The sense of direction—up, down, left, right—was utterly distorted.
Dim paper lanterns glowed faintly from corners and overhead, while the air carried the scent of rotting wood and the faint trace of blood.
Aside from Enmu, the three Lower Rank demons were visibly uneasy, darting anxious glances in every direction.
What's going on... All Lower Ranks? Kamanue thought nervously. Where are Lower Rank Four and Five? Why are there only four of us?
He looked upward. Seated above was a woman in black, her eyes obscured by long dark hair, holding a biwa that emanated a faint aura of blood.
Where is this place? Is this that woman's Blood Demon Art?
As the three exchanged uncertain looks, the shadows of the space shifted slightly.
A bone-chilling presence rose from the darkness.
A woman's figure stepped silently out from the shadows.
She wore an exquisite dark kimono, its intricate patterns gleaming under the dim light, the wide sleeves swaying gently with her steps to reveal a pale wrist.
Her jet-black hair was neatly tied at the back of her head, every strand meticulously arranged. Her face was flawless, like the most delicate porcelain.
If not for the crimson, inhuman slit pupils in her eyes, Kamanue might have mistaken her for a courtesan from a pleasure district.
"Lower your heads. Kneel."
Buzz—
An overwhelming terror surged through their veins, an instinctive dread born from their blood.
Almost simultaneously, the Lower Rank demons fell to their knees, bowing low in reverence and fear.
It's Lord Muzan's voice! Damn it! Because his posture and aura feel different, I didn't realize it in time to prostrate myself!
Kamanue wanted to slap himself. How could he be so foolish? How did he fail to recognize Lord Muzan?
The woman before them was the progenitor of all demons, the source of all evil—Kibutsuji Muzan!
This was not his true form, but a disguise to conceal his identity. He usually appeared as a man, so it was no wonder Kamanue hadn't recognized him immediately.
"You are indeed foolish—and not just in this matter."
Muzan's voice was icy.
Eh?
Kamanue shuddered.
Lord Muzan can read my thoughts?
Before he could speak, Muzan continued coldly:
"Lower Rank Four and Lower Rank Five are dead. Both died on the same day."
"There is only one thing I wish to know: Why are the Lower Ranks so weak?"
"Did you think becoming one of the Twelve Kizuki was the end? Why have you not devoured more humans? Why have you not grown stronger? At the very least, become somewhat useful to me."
"For the past hundred years, the Upper Ranks have never changed. They are the ones who have slaughtered the Hashira time and time again. And what about you?"
His voice and gaze were like a freezing gale, sweeping across the Lower Ranks and making them tremble uncontrollably.
With open disgust, Muzan's eyes locked onto Rokuro.
"Rokuro." His voice was eerily gentle. "Why is your aura so feeble? Like a dog with its spine snapped."
Without even touching him, with a mere thought, Muzan violently invaded Rokuro's consciousness.
"Ugh—!"
Rokuro let out a shrill scream, clutching his head with one hand as agony akin to a red-hot iron being driven into his brain consumed him.
His memories were torn open and rifled through by an absolute force, and he could not resist in the slightest.
[Osaki Hachiman Shrine... a young demon slayer... a grotesque gray-black serrated blade...]
These images flooded into Muzan's mind, causing him to frown.
That brat looks somewhat familiar...
Then it struck him.
As the Lower Rank Five he valued most, Rui had been given extra demon blood by Muzan. Muzan had also planted a seed of his consciousness within him to allow for direct communication.
When Rui died, Muzan had naturally reviewed the memories stored within that seed.
In those final moments, aside from the detestable boy with the earrings—Tanjiro—and the swordsman who used Water Breathing—
This cold-faced youth had also been present.
Muzan delved deeper into Rokuro's sea of consciousness, ignoring his anguished screams, carefully examining everything about that boy.
That serrated blade exuding an ominous aura—could it truly devour a demon's power?
Muzan's flawless face tightened into a frown.
What is that? A new weapon from the Demon Slayer Corps? Or a new breathing style?
This was a variable he had never encountered in his long life. A trace of icy irritation flickered deep within his crimson slit pupils.
"Worthless."
With that cold judgment, Rokuro's body was suddenly lifted into the air by a twisted demon hand extended from Kibutsuji Muzan, clenched tightly in its grip.
"Why did you try to flee? He wasn't even a Hashira!"
"I'm terribly sorry! Please... please forgive me, Lord Muzan! I truly—"
Crunch!
With a violent squeeze, Rokuro's body was crushed midair by Kibutsuji Muzan.
Demon blood splattered down onto the remaining three Lower Ranks.
Though demons could not kill one another, that rule did not apply to the King of Demons.
Countless grotesque mouths opened along Muzan's twisted arm, quickly devouring Rokuro's mangled flesh as though such a demon had never existed in this world.
"I believe... the Twelve Kizuki require only the Upper Ranks. I can no longer find any meaning in your existence. What do you think?"
Wakuraba and Kamanue froze, terror and fury churning within them as they struggled to believe what they had just heard.
Lower Rank One, Enmu, however, flushed red and began trembling violently.
"Lord Muzan! My purpose in existing... is to become your most useful tool!"
"To consume all your troubles! To clear away every obstacle that offends your eyes! To drag those foolish demon slayers into eternal nightmares of suffering! To make them wail in endless despair! What could be more important than that?"
"This is my only value in living! This is the entirety of my existence!"
"If you deem us useless, then my purpose is to satisfy your desire to kill, to quell your wrath..."
"How blissful... truly blissful..."
He tilted his head back, arms spread wide, his cloudy eyes nearly bulging from their sockets.
His lips stretched into an inhuman grin. Whether it was genuine or calculated flattery was impossible to tell, but the fervor on his face was beyond imitation.
"Shut up! Are you trying to get us killed?!"
"Stop it, you lunatic!"
Wakuraba and Kamanue were terrified out of their wits by this mad declaration, screaming instinctively.
Muzan narrowed his eyes and let out a cold laugh, raising his twisted demon claw high.
"...Silver-tongued little brat."
Bang! Bang!
But the target of the claw was Wakuraba and Kamanue.