"What did you say?!" Kibutsuji Muzan's face split with rage; no one had ever dared mock him like that.
Facing Muzan's furious glare, the Divine Priest replied coolly, "Is there something wrong with what I said? Two people already exist who can slay you — isn't that enough? You have no choice but to cooperate with me if you want any chance."
Muzan gradually calmed. The situation was indeed dire: "I wiped out your Divine Priest clan — why would I choose to cooperate with you?"
"I intend to remove the single greatest variable in this world and return things to their proper course."
Muzan frowned and pressed: "The greatest variable? Who?"
"Yōsuke Ubuyashiki."
Hearing that name, Muzan felt no surprise; if anything, he thought only Yōsuke Ubuyashiki was worthy of being called such a variable.
"Yōsuke Ubuyashiki? Why is he the greatest variable in the world?"
The Divine Priest explained, "Kibutsuji Muzan, your becoming the Demon King was arranged by fate — but Yōsuke Ubuyashiki was not meant to be. The world does not need two origin Demon Kings."
"Arranged by fate?"
The Divine Priest continued, "That's right. The world required the existence of demons, so we chose you. You lacked human sensibility and empathy, which made you suitable.
"But on the day only you were meant to become the Origin Demon, something went wrong: Yōsuke Ubuyashiki — someone who ought never to have existed as a demon — became one. From that day on, fate was thrown into chaos."
Muzan sneered, "Absurd. You claim you made me the Demon King? Who do you think you are?"
The Divine Priest replied calmly, "I state only the facts, and I have lived far longer than you. I was born in the Jōmon period."
Muzan was stunned. "Impossible! The Jōmon period was ten thousand years ago — how could you have survived ten thousand years?!"
"I have no reason to deceive you. In the Jōmon era, people still lived in caves and led a primitive life. At that time, a naive version of me received fate's instruction and became the Divine Priest, establishing the Divine Priest clan. I guided humanity to develop into tribes and begin new lives of gathering, fishing, and hunting. In other words, I founded the era of this nation."
The Divine Priest's words left Muzan utterly incredulous. "I don't believe it! If you stood on humanity's side, why then make me a demon?"
"I do not stand for humanity; I always stand for fate. Since fate ordained you to become the Demon King, it is my responsibility to carry out fate's directive.
"Before demons were born, humans evolved from tribes into larger states and wars erupted continuously. Through endless wars the world was rent and scarred. To make humans experience suffering and thus learn the value of peace, demons were born.
"Your original end was to be slain by the child of fate chosen by this world, so that the land ravaged by malevolent demons could be reborn."
Muzan seemed to teeter on the brink of madness. "A thousand years… was I merely a puppet to fulfill some so-called divine order? I refuse to believe it!"
The Divine Priest's figure flickered and he appeared right before Muzan, touching his forehead with one finger.
A vivid scene flooded Muzan's mind, as if he were living it himself.
On some battlefield, Demon Slayer Corps swordsmen charged at him without hesitation, fighting him to the death.
At that moment Muzan was afflicted by a complex cocktail of four medicines: the "human-transformation drug," the "aging drug," the "anti-division drug," and the "cell-destructive drug."
Muzan had managed to decompose and overcome the human-transformation drug on the spot, but once decomposed it became a potion that caused rapid aging — accelerating him fifty years every minute. Muzan, already nine thousand years aged, thus grew rapidly older.
When Muzan attempted to split himself to escape the fight, the third and fourth drugs took effect. Under a relentless barrage that continually assaulted and weakened him, he could not divide and his strength dwindled to near exhaustion — utterly broken.
Pinned to the wall in that state, his arms torn off, Muzan, facing the coming dawn, tried desperately to bulk his body up into a "giant infant" to burrow underground and avoid the sunlight.
But in the end the Demon Slayer Corps, pouring everything they had into the effort, dragged Muzan into the sunlight.
Muzan could only fall, unwilling and terrified, into hell — his thousand years of terror and tragedy finally dissipating from the world.
The vision in Muzan's mind stopped.
The Divine Priest smiled faintly and asked, "Well? That is your final ending. What do you think?"
Muzan's face was dark with fury. "I don't like it!"
The Divine Priest continued, "Even without Yōsuke Ubuyashiki, you would not succeed. And now, because of Yōsuke Ubuyashiki's intervention, the chance for a world ravaged by demons to be reborn has already failed. That is why we must cooperate — to slay Yōsuke Ubuyashiki. It is your only opportunity."
Muzan still did not trust the Divine Priest; he suspected some special power at work. "If you've survived for tens of thousands of years and your strength is unfathomable, why didn't you deal with Yōsuke Ubuyashiki from the start?"
The Divine Priest explained, "I once tried. Yōsuke Ubuyashiki was struck by a serious illness the moment he was born — that was my doing. Unfortunately, he did not die.
"Given his condition, even taking the demon-transforming medicine should not have been enough for his body to become a demon. Yet a mysterious power within him cleansed the body's fatal flaws when he took the medicine, and he successfully became a demon.
"After that, fate was thrown into disorder. Yōsuke Ubuyashiki became part of fate's tapestry, and I could not personally intervene against him."
Muzan pressed on, "You say you could not act — so why now seek me out to cooperate in killing Yōsuke Ubuyashiki?"
"I still cannot personally slay Yōsuke Ubuyashiki. Once I became the Divine Priest and accepted fate's oracle, I was forbidden from directly taking action against any being who has become part of fate's design.
"But you can. Kibutsuji Muzan, you and Yōsuke Ubuyashiki share the same origin. If anyone in this world can kill Yōsuke Ubuyashiki, it is you."
Muzan sneered coldly, "And if I kill Yōsuke Ubuyashiki and the ending remains the same? If cooperating with you yields me no benefit, why should I help?"