The reason the Hashira struggle against the Upper Moons isn't because of inferior skill, but because of the vast difference in physical constitution.
In head-on combat, skilled Hashira can match Upper Moons in technique and strength. Some have even repelled them before.
But demons can regenerate. When equally matched, the Upper Moons can easily wear the Hashira down with their ability to heal—so long as their heads remain intact, they can exchange injuries until the humans collapse.
This is humanity's weakness: their bodies are simply inferior to demons'.
Aside from decapitation by a Nichirin blade or exposure to sunlight, demons are virtually indestructible.
If Kawanishi one day reached the strength of an Upper Moon while retaining his humanity, it would be a huge boon for the Demon Slayer Corps.
In emergencies, Kawanishi could act as a vanguard, lowering the death rate of Hashira.
Thinking of his old comrades, Urokodaki Sakonji couldn't help but feel sorrowful.
As a former Water Hashira, it was already remarkable that he'd survived to old age and retired—it made him very lucky.
But how many of his fellow Hashira had survived?
At this, Urokodaki recalled Kawanishi mentioning the First Demon and asked, "Where did you get your information on Muzan Kibutsuji?"
"He's always been elusive. The Demon Slayer Corps has searched endlessly for him. Only by killing him can we end this scourge once and for all."
"So long as he lives, no matter how many demons we slay, Muzan will keep creating more. This battle will never end."
Muzan's whereabouts were always shrouded in mystery—he had never directly clashed with the Demon Slayer Corps.
Kawanishi voiced his confusion: "That doesn't make sense. If even an Upper Moon is enough to challenge the strongest Hashira, why would Muzan hide? He could openly appear and still be difficult to confront."
Urokodaki chuckled: "Because Muzan is, at his core, a coward terrified of death. Without absolute certainty, he would never expose himself to danger."
Before Kawanishi could respond, Urokodaki looked up at the ceiling and asked, "Do you believe Muzan is the most powerful being in this world?"
Unsure, Kawanishi still answered honestly: "Yes, I do."
"Even if you found him, even if dozens surrounded him, countless swordsmen would surely die before they could take him down—especially since he commands far more demons than we have swordsmen."
But Urokodaki shook his head. "You're wrong."
"The true ceiling of this world's power has always been humans."
"That's why Muzan remains cautious—he fears us."
Because once, Muzan was nearly slain.
Hearing this, Kawanishi was stunned. "What do you mean? There's a human stronger than Muzan? A Hashira?"
"In those days, there were no Hashira yet," Urokodaki explained.
"He was the founder of Breathing Styles. The very person whose techniques birthed all modern forms of breathing that allow us to fight demons."
"All we have now traces back to him."
Hearing this, Kawanishi felt a surge of awe. He had personally experienced the power of the Hinokami Kagura; now he learned that all breathing styles originated from a single man.
Urokodaki continued in a deep, solemn voice: "Four hundred years ago, during the Sengoku era, a man mastered the first breathing style: Sun Breathing. His name was Yoriichi Tsugikuni."
"At just twenty-something years old, he was already an invincible god among men."
"At such a young age, he stood atop the world."
"Once, Yoriichi and the Demon Slayer Corps cornered Muzan Kibutsuji."
"At that time, Muzan was arrogant and reckless, so the Corps easily located him—but his minions tried to block their path."
"Yoriichi broke through alone and confronted Muzan directly."
"With a single strike, he forced Muzan to the brink of death—this was the most severe injury Muzan ever suffered, both physically and psychologically."
"Unfortunately, Yoriichi was momentarily distracted by Upper Moon One, Kokushibo, allowing Muzan to escape."
At this point, Urokodaki sighed.
Had Kokushibo not interfered, Muzan would have been destroyed. Demons would exist only in stories, and the world would be at peace.
When Urokodaki read this history in the Corps' records, he couldn't help but feel regret.
If only Yoriichi hadn't been distracted.
But one mystery lingered—how could even someone as godlike as Yoriichi be thrown off by Kokushibo?
The official records only vaguely noted Kokushibo's interference, never explaining the reason.
Even as a former Water Hashira, Urokodaki didn't know the full truth; he assumed the successive Corps leaders must have known, but never inquired further.
"So you see, Muzan is nothing but a powerful coward. While Yoriichi lived, he was like a pebble in the sea—unable to stir even the slightest ripple, hiding until Yoriichi's death."
"Even after Yoriichi passed, the fear remained. Muzan has lived cautiously ever since, his whereabouts always shrouded in secrecy."
"That's why any information about him is vital."
While ordinary demon slayers feared Muzan, those like Urokodaki, who had pursued him for decades, only felt contempt.
He was nothing but a coward wielding immense power.
When Urokodaki finished, Kawanishi couldn't help but sigh.
"To think such a history exists… Muzan isn't invincible after all."
No matter how strong Kawanishi's resolve burned for revenge, he understood Muzan's terrifying power.
He often comforted himself, believing he'd grow stronger and one day slay Muzan—but whether that day would come before his death was uncertain.
Yet knowing someone stronger than Muzan once existed filled him with hope.
So even Muzan has known fear.
Urokodaki straightened his posture and asked with utmost seriousness, "Now then—this information you have on Muzan Kibutsuji: is it true? Can it be trusted?"
Seeing his grave expression, Kawanishi nodded solemnly. "I can guarantee it."
Soon after, Kawanishi explained everything about Tsukihiko and his ability to grow stronger by consuming demons.
Behind his tengu mask, Urokodaki's face grew ever more serious.
This Tsukihiko was very likely Muzan himself.
Records indicated that Muzan enjoyed masquerading as various people—his way of amusing himself through the endless boredom of immortality.
Urokodaki said grimly, "If your information is accurate, the Demon Slayer Corps may finally have a chance to cripple him—perhaps even kill him outright."
"I must report this to the Master immediately."
(End of Chapter)