A hoarse crow cried out in the quiet darkness of the forest. A few birds flapped their wings and flew out from among the trees. Black shadows darted across the full moon, making the leaves shiver in the faint night breeze.
Muzan took advantage of the darkness to return to his residence. The moment he stepped inside, he saw the blood still smeared on his lips reflected in the mirror. He raised a handkerchief and wiped it clean.
Five days ago, he had suddenly died… and crossed over through time.
Because his soul was overloaded with kinetic energy when entering this world, it shattered the original soul — and Muzan had fainted.
He had succeeded in taking over the body, and in the process, absorbed the previous owner's memories.
The method was strange, but irrelevant.
What really mattered was this: staying up late genuinely could kill you.
Before the body swap, the previous owner — a scummy villain — had turned a doctor into a ghost unwillingly, and the doctor now lived in his house.
Now that Muzan had returned, the doctor, Yanagisawa Jixing, bowed respectfully. "Sir… welcome back," he greeted, waiting until Muzan entered the room before resuming his own work.
Yanagisawa Jixing had been chosen by the original Muzan to become a ghost because of his medical expertise.
But unlike the previous scumbag, Yanagisawa's character was infinitely better. Even as a ghost, he didn't just feed on humans indiscriminately — he attacked only the extremely wicked, and healed anyone worthy of saving.
The original Muzan had been deeply annoyed by this. If he hadn't needed the doctor's skills, he'd have killed him outright. But the current Muzan was far more tolerable to be around.
Once inside his room, Muzan pulled a thick medical book from the shelf and sat cross-legged on the ground to read.
He never expected that after crossing over, he would sit down calmly to read — and of all things, medical textbooks he used to find unbearably boring.
Maybe it was the influence of the memories he absorbed… or maybe this era was just painfully dull.
It was still the year 1467 — during the Warring States period in this island nation — and there was virtually nothing entertaining.
He planned to wait for the day smartphones appeared. Until then, if he didn't study something, he might literally go mad.
As dawn crept in and morning light filtered through the paper windows, Muzan felt the sunlight pricking his skin. He found a piece of black cloth to block it and went back to reading.
Thanks to being a ghost, darkness and light made no difference to his vision — he could read perfectly.
Meanwhile, Yanagisawa Jixing continued waiting for patients as if he still practiced human medicine — all the while taking samples of Muzan's blood to study ways to overcome sunlight.
But Muzan had already seen what he was trying to do:
It's impossible. Truly impossible.
He was just an ordinary doctor — maybe slightly above average — but there was simply no medical method to allow ghosts to withstand sunlight.
Five centimeters thick, Muzan's book was opened to the final page. His notes filled entire sheets of paper in tiny, neat handwriting. Closing the book, he put both it and his notes back on the shelf and stood.
The door to the outer room was half closed. Muzan pushed it open and saw Yanagisawa flipping through another thick book. The paper beside him was densely covered in notes, and his expression looked painful — the same look as a student stuck on the final math problem of the national college entrance exam.
He was struggling to fulfill the demands of the scummy boss — beyond his skill level — but working on it anyway.
Seeing his cruel, ruthless boss approaching, his body stiffened. He swallowed hard and stood respectfully, eyes lowered, afraid to speak.
Muzan, used to the behavior of his demon subordinates by now, lifted the thick book from the table.
"Don't waste effort on what you cannot achieve," he said flatly.
Yanagisawa went even paler, sweat beading on his forehead. His voice trembled, "Sir… I can do it! I will do it!"
Muzan stared at him, utterly unamused, as though afraid he might be snapped in half by the gaze.
"I won't kill you. Just improve your medical skills at your own pace," he said, then took up his big book and turned to leave.
The book was the real reason he came back — telling the doctor not to overwork himself was just a bonus.
Dong…
A light sound came from outside the wooden door. Muzan paused, turned, and pulled up a small stool to sit beside it, curious.
Yanagisawa glanced at Muzan, then said softly, "Come in."
Three figures wearing Demon Slayer Corps uniforms stepped through the door quickly, daggers sheathed at their sides. Two of them held a person between them — supported on the left and right.
At the sight of them, Yanagisawa froze — instinctively wanting to retreat.
But Muzan's voice echoed in his mind:
Be calm… we are here to save them from you.
To be honest, Muzan was momentarily stunned when he saw them — but relieved once he realized they had knocked and been admitted, and none looked particularly strong. They likely couldn't tell that he and Yanagisawa were ghosts.
The person in the middle was soaked in blood, and the uniforms of the other two were torn with wounds on their arms and shoulders.
How amusing — the Demon Slayer Corps had come for treatment from demons.
Muzan Kibutsuji had five brains and seven hearts. Not only did this grant incredible memory and intelligence, he could monitor his ghosts at any time.
Ever since crossing over, though, he had been too lazy to keep track of them.
Seeing this, he checked the status of his ghosts.
Had some nearby run into Demon Slayers?
Hearing Muzan's thoughts, Yanagisawa let them lay the injured man on the nearby bed to examine him — though his expression was awkward.
He didn't dare heal a member of the Demon Slayer Corps!
Doctors were kind by nature, but preserving his own life was more important than dying for a stranger.
"Treat him," Muzan commanded.
Yanagisawa hesitated… then Muzan's voice came again.
Finally, he relaxed and asked bluntly, "How were you so badly injured?"
In the Warring States Era, cannibalistic ghosts were known and feared — regarded among gods and demons — and widely recognized by the people.
The youngest of the Demon Slayers leaned his Nichirin sword against the bed and sat down, voice angry.
"We ran into bandits! Terrible trash! We got ambushed!"
The other slayer grumbled as well, "They got away! Damn it!"
Yanagisawa cleaned his wounds while replying, "Ah… this world is truly chaotic…"
"By the way," he continued, "try not to go out at night. Another person nearby was taken by a ghost again."
Yanagisawa said this while considering whether to relocate — this chaos, with bandits and war everywhere, meant danger at every turn. Staying in one place too long would mean certain discovery.
After the Demon Slayers had left, Muzan looked at Yanagisawa.
"Don't worry. They were talking about another ghost."
Though Muzan hadn't made many ghosts, the population in Edo was still dense.
"And tonight… you should deal with the bandits and bring one back," he said.