The original Breathing Style, the strongest swordsman, the legendary demon hunter.
This was how the successive Flame Hashira recorded Yoriichi Tsugikuni.
Autumn weighed heavily upon the courtyard, pressing even the few old maple trees into a stoop.
Withered yellow leaves spiraled down, blanketing the stone slabs and crunching dryly underfoot.
In the corner of the yard stood a sword rack. Upon it lay a Nichirin Blade in a crimson scabbard, resting quietly. The flame motif on its tsuba was dim and lifeless.
This was the Rengoku family dojo, and for the time being, the place where a "prisoner" was being held.
The door slid open softly, letting in a trace of cool air.
Flame Hashira Rengoku Eijuro's tall figure appeared beneath the eaves. In one hand he carried a small, plain clay sake flask; in the other, two equally unadorned cups.
His thick brows were tightly knit. Without a word, he sat beside the silent man, a hint of worry flickering in his golden-red eyes.
"Lord Yoriichi, would you care for some?" he asked gently, offering the cup.
The man beside him wore a red outer robe. His long, dark crimson hair was tied high in a ponytail, and red markings like flames spread across half his face. A steady, rock-like composure emanated from him.
He accepted the cup and nodded. "Thank you."
Even today, when the Demon Slayer Corps was about to pass judgment on him, his eyes—clear as sunlight piercing the netherworld—remained calm and transparent, devoid of sorrow or joy.
He was Yoriichi Tsugikuni, the strongest swordsman of the present age.
"The other Hashira and the elders of Ubuyashiki are somewhat dissatisfied with you..." Eijuro lifted his cup but did not drink, staring instead at the liquid within. "About Muzan not being executed, about letting that demon escape, and..."
He did not finish.
The most dreadful crime of all.
Yoriichi's elder brother—the powerful swordsman Tsugikuni Michikatsu, whom he himself had introduced into the Corps—had slain the current Master and fled with the Ubuyashiki head!
Yoriichi did not respond.
The Flame Hashira drank a mouthful of sake in frustration. He did not know what punishment awaited this selfless swordsman who had taught everyone the Breathing Techniques, and his heart was heavy.
"Lord Yoriichi! I want to know—what kind of monster is Kibutsuji Muzan?"
"Could even your blade not kill him?"
At the mention of that name, Yoriichi fell silent and took a sip of sake. His gaze drifted toward the wind-tossed leaves, seeming to pierce through the bleak scenery before him and into a far older, darker place.
"Muzan..." His lips parted, his voice carrying a chill. "I encountered him in a bamboo forest outside Kyoto..."
Late autumn, in the outskirts of Kyoto. Deep within a vast bamboo grove.
Tall green stalks intertwined overhead, their leaves forming a dense canopy that filtered the daylight into a shadowed sea of green.
At the time, I walked there alone.
Suddenly—
A viscous, icy malice seeped from the depths of the forest without warning and invaded my senses.
I had already entered the realm of the Transparent World. Even the faintest stir of wind and grass in the mortal world could not escape me, let alone such a repulsive presence.
In the layered, bottomless gloom of the bamboo grove stood a "man."
Though he bore the appearance of a human male, I could clearly see that he possessed five brains and seven hearts. His entire body radiated a nauseating aura.
Beneath that handsome shell writhed a grotesque, evil soul, as though it sought to devour all other life.
At first sight, I knew who he was—Kibutsuji Muzan.
At the same time, I felt something with unprecedented clarity: perhaps the reason I was born into this world was to defeat the one standing before me.
When my hand settled on the sword at my waist, he noticed me as well.
He made no effort to conceal himself. Beside him stood a woman—also a demon.
Muzan stood there elegantly, a cat-toying-with-a-mouse smile curling his lips.
"To be honest, I've grown rather tired of you Demon Slayer swordsmen and your so-called Breathing Techniques," he said.
In the next instant, his figure blurred where he stood.
A thunderous blast followed. The ground where he had been exploded in a cloud of smoke, shaking the surrounding bamboo violently and sending leaves cascading like torrential rain.
In the blink of an eye, he was before me—so fast it nearly surpassed the limits of human perception.
His right hand spread wide, nails gleaming like obsidian in the dim light, reaching straight for my head.
I dodged swiftly. Behind me, swaths of bamboo were severed by his mutated demon claws.
"To be honest, since the day I was born, it was the first time I had encountered such an enemy... For the first time, I felt the joy of battle," Yoriichi recalled.
"And then?" Eijuro tightened his grip on the cup, pressing for more.
"After that... I used the strongest sword technique I could unleash."
"The Thirteenth Form of Sun Breathing."
Sizzle—!!
The playful crimson in Muzan's eyes froze, instantly overtaken by disbelief and terror.
Too fast! So fast that there was no time even for fear or evasion!
In a single instant, accompanied by the sound of a heated blade slicing through butter, Muzan's body was cut into multiple pieces!
In over a hundred years, not to mention being severed like this—there had not even been anyone capable of wounding him!
More terrifying still, the blazing Nichirin light suppressed his regeneration!
Yoriichi's blade burned like molten steel, scorching and radiant. The ugly mark on his face seemed to come alive, transforming into flowing tongues of flame.
He stepped toward Muzan, eyes cold as judgment upon the progenitor of demons.
"For what purpose do you live?"
"What pleasure is there in killing?"
"What do you take life to be?"
"Heh... heh..." Muzan's lips trembled weakly, emitting meaningless gasps as he glared venomously at Yoriichi.
No! I cannot die! Not here! I am perfect! I am the eternal Demon King!
The instinct to survive overwhelmed everything! His scarlet eyes, filled with fear, hatred, rage, and cowardice, burst with desperate madness.
"Aaaahhh—!!!"
A nonhuman scream of terror tore from his throat, shrill as the wailing of countless hellish demons, shaking loose another storm of bamboo leaves.
Bang!!!
Without warning, his body exploded—instantly splitting into over eighteen hundred tiny fragments!
They shot outward in every direction—up, down, left, right—into every possible crevice of the forest, fleeing in frantic desperation!
Each chunk of flesh was wrapped in writhing black demon aura, like a black meteor shower erupting within the bamboo grove!
This was Muzan's final life-saving trump card.
An ultimate evil art that discarded all dignity and form in exchange for a single thread of survival.
Yoriichi reacted at the very moment Muzan split apart. He swung his Nichirin Blade with everything he had, striving to annihilate the demon!
Boom—!!
Boundless fiery blade-light flared like a golden crow descending to the mortal realm!
Golden-red flames that could incinerate all things roared and spun around Yoriichi, weaving into a blazing net that engulfed the vast majority of Muzan's scattered flesh in an instant!
Sizzle sizzle sizzle—!!!
The air filled with a suffocating stench of charred flesh.
Countless black-shrouded chunks shrieked within the radiant blade-light, reduced to drifting strands of black smoke.
The smoke twisted like countless screaming faces before dissolving in the flames.
"And even so, I only destroyed about fifteen hundred of the fragments... Muzan still escaped..."
"That is all. I am sorry for disappointing everyone."
In the courtyard, Yoriichi's voice fell calmly on the final syllable.
He raised the cup before him and drained the now-cool sake in one swallow, his gaze drifting once more toward the horizon.
The cup in Rengoku Eijuro's hand had already tilted. Sake soaked into his hakama, yet he did not notice.
He sat frozen in place, as though encased in invisible ice.
"Even you... could not kill him..."
...Time passed. These words and memories were recorded by Eijuro, passed down through generations, and eventually presented before Asuka and Kyojuro.
Asuka finished reading the account with a deep frown. He cared little for their self-reproach. Only two things captured his attention.
Yoriichi Tsugikuni's blade could ignite as well...
And he, too, bore a mark upon his face.