Kyoto
Infinity Castle
Crack...
The test tube in Muzan Kibutsuji's hand shattered.
"Another failure."
He had lost count of how many times his experiments had failed.
Irritation gnawed at him.
As frustration welled up, he couldn't help but think back to that fateful moment when he killed the doctor a thousand years ago.
I should've never killed him before figuring out what the Blue Spider Lily actually was.
For centuries, he had scoured medical texts from both Japan and abroad, yet there was no mention of the Blue Spider Lily anywhere.
"Damn it… that bastard Yoriichi Tsugikuni from five hundred years ago, the wound he gave me still hasn't fully healed."
Muzan clutched his chest, feeling a dull ache.
It had taken him centuries to outlive Yoriichi and eradicate his legacy.
Coupled with his five-hundred-year-old development of the Blood Demon Art: Infinity Castle, Muzan had thought himself untouchable.
But then, out of nowhere, the gods appeared.
A single blessing from them had made the Demon Slayers stronger than Yoriichi ever was.
To avoid being discovered, Muzan had been forced to stop all his activities in the outside world, severing contact with all his demons.
I created demons to serve me, to search for anything of value to aid my quest.
But in all these centuries, how many demons had I created? Not a single one brought anything useful to me.
He began to doubt if creating so many demons had been a mistake.
If I hadn't created so many, Yoriichi wouldn't have existed, and I wouldn't have attracted the attention of the gods.
The more Muzan thought about it, the angrier he became.
It all started five hundred years ago when Yoriichi developed the breathing techniques that gave birth to the Hashira. The Demon Slayer Corps began promoting members to Hashira only after they killed a Lower Moon of the Twelve Kizuki.
What an insult.
It was as if the only purpose of the Twelve Kizuki was to help Demon Slayers rise in rank.
Just as these thoughts churned in his mind, the memories of an Upper Moon demon's death flooded into his consciousness.
Muzan wasn't initially alarmed by the death of an Upper Moon.
He had already written off all demons outside Infinity Castle.
Those Demon Slayers, empowered by divine blessings, are stronger than Yoriichi ever was. Killing an Upper Moon for them is no different than slicing through bamboo.
Even if all the demons were wiped out, Muzan wouldn't care.
They were nothing but tools to him. As long as they didn't cause him direct trouble, he had no attachment to them.
But when he received Gyutaro's memories, real panic set in.
And this time, it was absolute.
The Demon Slayers knew about Infinity Castle.
In an instant, everything became clear.
It must have been the gods who told them.
And then there was the mention of those paper cranes they used to track demons.
He wasn't sure if those cranes could find Infinity Castle, but the mere fact that the castle's existence was known meant it was no longer safe.
If they kill all the demons, or if the number drops below fifty, my whereabouts will be exposed!
Muzan wasn't sure if the Demon Slayers were bluffing, but he couldn't afford to take that risk.
As long as I remain on this land, I will be found…
Fear gripped him, swelling inside like a dark tide.
He knew it was true. After all, there were gods watching over this land.
Sweat dripped from his forehead as he paced, the vast emptiness of Infinity Castle echoing only with his footsteps.
"There's only one option left."
He tugged his hat lower, casting a cold, shadowed gaze at Nakime, the demon seated nearby, playing her biwa.
"Die."
"Ah..." Nakime's body twisted and contorted as Muzan's curse ripped through her. Her eyes bulged grotesquely as she looked at him, her body swelling like rotting flesh.
"Muzan...sama..."
"Infinity Castle is useless to me now. So are you," Muzan said coldly.
Though he was the progenitor of all demons, Muzan was cowardly, with none of the grandeur expected of a ruler.
To him, demons were nothing but tools—disposable if they failed, irritated him, or even leaked the slightest bit of information.
Nakime, understanding the kind of master she served, was left speechless. She knew better than anyone how ruthless Muzan could be.
The Demon King who ruled through fear and violence, eliminating any demon that displeased him, no matter their rank.
Even the Upper Moons were not exempt.
She didn't know what she had done to anger him, but there was no time to contemplate it—she was already dying.
As Nakime perished, Infinity Castle began to collapse.
Muzan now stood alone in a dense forest, his hat pulled low to conceal his face. His glowing red eyes scanned the distant lights of a bustling city.
"As long as the number of demons drops below fifty, I will be found. So before I leave this land, I'll have to increase their numbers."
He decided to leave this land, to cross the seas and escape to a foreign country.
There shouldn't be any gods over there.
To ensure that the Demon Slayer Corps wouldn't somehow track him down during his escape, he made a plan to create as many demons as possible to stir up chaos and divert their attention.
They'll be so focused on fighting the demons that they won't have time to bother with me.
In the past, he would never have created demons in such large numbers. If he attracted the attention of the nation's higher powers and they mobilized the country's forces against him, it would bring him no advantage.
That's why he had always ordered his demons to remain discreet, even when devouring humans. They were to avoid drawing attention at all costs.
But now things were different. The fewer demons there were, the more of a threat they posed to him.
Demons must be numerous. The greater the chaos they cause, the safer I'll be.
As for the nation's royalty and nobility...
If I turn all of you into demons, both the gods and the Demon Slayer Corps will be in complete disarray, won't they?
Muzan's expression twisted into something strange.
How did I not think of this before?
If he had turned the royalty and the aristocracy into demons back then, the nation's resources would have been at his disposal for searching for the Blue Spider Lily. Surely, with their power, they would have found it by now.
By the time he became a perfect being, he wouldn't have had to fear the nation's forces at all.
He could have changed his appearance, even his gender, and no one would have ever suspected that the Demon King was the one who had turned the royal family and nobility into demons.
In Tokyo, Chiyoda District, at the Imperial Palace in Katsura Imperial Villa...
The current Emperor was pacing back and forth, contemplating how to force the nobility to surrender their power and modernize the country's system. His goal was to transform the nation into a war machine capable of claiming a share of Asia as European powers carved up the continent.
"Those damn regional lords... Damn the shogunate! Even as the Emperor of this nation, I have no authority over the military," he muttered angrily.
At that moment, a magnetic voice echoed from behind him.
"So... you desire power? How about I give you power?"
"Who's there?" The Emperor spun around in shock, but before he could fully react, a single finger pierced the back of his skull.
"Aaaargh!"