--The Yaoshi's Ambition!
Tokyo, suburbs.
A Western-style hospital abandoned by war and long abandoned.
This is the temporary base of Upper Rank Seven, "Yaoshi".
Right now, this newly promoted Upper Rank demon is sitting in his spacious office, reviewing his work reports from the past three months.
In front of him was a desk.
There were no bottles or jars on the table that smelled of formaldehyde.
There was only a cup of steaming Ceylon tea and medical records written on the finest washi paper.
If you ignore the bizarre titles in the file, such as melancholic syndrome, compulsive inverted personality, and mushroom-like mutation, you'll find them strange.
The scene before me was like a painting, a beautiful oil painting depicting a top scholar enjoying a leisurely afternoon of work.
However, the scholar's mood was far from pleasant.
"Snap."
He casually closed a file, then rubbed his temples with two long, slender fingers in frustration.
"A failed product."
His voice was soft and refined, like the gentlest yet cruelest comment he could give to a failing student.
[Medical Record Number: 073]
[Experimental Topic: Study on the Enhancement Threshold of Demon King Cells on the Physical Functions of Ordinary Demons]
[Experimental Subject: A poor wretch who was fired by Muzan for Muzan performance but miraculously escaped death]
[Experimental Procedure: With his "voluntary" consent, 0.5 ml of my carefully purified Source Blood was injected into his body.]
Experimental Results:
After enduring three minutes of agonizing screams, the test subject exploded violently.
The explosion was roughly equivalent to a bundle of cheap fireworks, and it even soiled three square centimeters of my white lab coat.
[Conclusion: Some useless people, even if given the chance to rise to the top overnight, only deserve to become a pile of worthless organic fertilizer.]
[Note: Next time, perhaps we could try lowering the concentration of the Source Blood a little.]
After all, not everyone is qualified to appreciate my modified work of art.
He picked up his black tea, took a small sip, and tried to use the rich aroma to calm his agitated mood, which had been aggravated by seeing so many idiots.
But it's completely useless.
He picked up the next file.
[Medical Record Number: 121]
[Experimental Topic: Observation of the infectivity and hallucinogenic effects of Delusion Neurotoxins in a group setting]
[Experiment Location: A Demon Slayer Corps base in eastern Taiwan]
[Experimental Procedure:]
I used a crow that I had deeply hypnotized to release Blue Virus at the base's water source.
Experimental Results:
All thirty-seven Demon Slayer Corps members at this base were poisoned.
Ninety percent of the test subjects exhibited symptoms of collective melancholy.
They held the dead sparrow, crying like a bunch of 300-pound children, successfully making me seriously question the definition of the word "macho man."
[Conclusion: The hallucinogenic effects of the Blue Virus seem to undergo unpredictable, but ultimately useless, mutations due to the subconscious of the test subjects.]
[Note: Perhaps I should release some viruses into them about Muzan- sama's hula-dancing illusion. That scene would be extremely, extremely interesting.]
"Snap."
He closed another file.
His facial expression became even more displeased.
For the past three months, following Muzan's instructions, he unleashed wave after wave of plagues throughout Japan with near-mad efficiency.
Like a high and mighty god, he enthusiastically cast his colorful works of art upon the world.
He watched as those so-called elite swordsmen made a fool of themselves or turned on each other in the face of his virus.
He watched as the Demon Slayer Corps, their supposedly proud medical unit, was utterly helpless and exhausted in the face of his masterpiece.
He enjoyed the feeling.
This absolute sense of superiority comes from having everyone manipulated and controlling their lives.
But!!
His core and fundamental research topic was the selection and creation of perfect experimental subjects.
But, there was absolutely no progress!!
Whether they were strong ordinary people he captured or low-level ghosts he "persuaded" with force.
Not a single one!!
Not a single test subject could successfully carry his improved, perfect bloodline!!
They were like inferior containers, utterly incapable of containing his work of art, which was nothing short of divine nectar!
They'll either burst from being stuffed, or turn into a mad, drooling mess of flesh.
Waste!!
They're all useless!!
"It seems... casting a wide net won't work..."
Just like no matter how many grains of sand you have, you can't build a diamond.
"What I need is not quantity."
"It is a source of extremely high-quality, perfect raw materials from the very beginning."
The Yaoshi leaned back in his chair, his long, slender fingers rhythmically tapping the table.
His gaze passed through the window and landed on the pale, cold moon.
"Blue Spider Lily..."
He murmured the name that haunted his dreams and made Muzan increasingly impatient.
Where are you?
Based on Muzan's description filled with rage, and the fragmented records he himself collected from countless ancient texts...
"Wait a moment..."
The Yaoshi's fingers, which were tapping on the table, suddenly stopped.
A crazy idea suddenly took shape in his mind.
Could it be that this damned flower only blooms during the day?
The moment this thought appeared, it spread like wildfire in his mind, replicating and multiplying rapidly!
Right!!
That must be it!!
A miraculous flower that blooms only briefly during the day, or even only at midday when the sun is strongest!
This perfectly explains why Lord Muzan spent over a thousand years trying to find its trace!
Because, from the very beginning, the direction of the search was wrong!!
"Hehe... hehe..."
A low, excited laugh escaped the Yaoshi's throat.
"Muzan... Although you are the progenitor of all demons, your mind is still bound by the pitiful identity of being a demon..."
"But I am different."
"I am a scientist."
"A transcendent being who dares to question everything and challenge all conventional wisdom!!"
He stood up, walked to the window, and looked at his face, which appeared even more handsome and refined in the moonlight.
In his eyes, a glint of ambition shone.
He was tired of this life of hiding and running around like a rat in the street, being chased all over the world by that damned expressionless Water Hashira.
He was already tired of this life where he had to be Muzan to Lord Muzan and fawn over him like a dog.
He needs to change his strategy.
He's going to take a huge gamble.
A gamble that involves risking everything, and the future of the world... the ultimate high-stakes gamble!!
He decided to halt this widespread and pointless spread of the plague.
That kind of crude, undisguised, and brute-like method is unworthy of his noble status as Yaoshi.
He needs to disguise himself.
Disguised as a human.
A kind-hearted doctor who travels far and wide, practicing medicine to help the needy.
He was going to the most remote, secluded mountain villages, the ones most likely to have ancient legends.
He wanted to use his superb medical skills to cure the ignorant villagers who were tormented by illness.
Then, while they were filled with gratitude and worshipped themselves as gods.
Then, "casually" ask them about it.
I'm inquiring about a type of blue flower that blooms only during the day.
"Then, let's begin with... the closest mountain to here... Mount Kumotori."
A confident and elegant smile, as if everything was under control, appeared on the Yaoshi's lips.
He turned around, went back to his desk, and burned all the medical records, along with everything else on the desk.
Flames burned fiercely in his eyes.
He walked out of the abandoned hospital, filled with death and wailing, bathed in moonlight.
He stood on the hill, and one last time, looked back.
That brightly lit city that never sleeps...
His face wore a gentle, compassionate smile, like that of a god.
Goodbye, my poor... patients.
"The next time we meet, I will be... your... god."