Morning sunlight streamed through the transparent windows, falling across the room. Murata stirred, blinking as he slowly climbed out of bed.
Around him, the other servants had already dressed and neatly folded their bedding. Murata let out a long sigh as he took in the unfamiliar room.
Yes, he was here undercover.
That said, "undercover" wasn't entirely accurate. This residence of Major Kuroda was not the lair of a demon. It was more precise to say he had come to infiltrate and investigate.
Murata, a rank-and-file member of the Demon Slayer Corps, had come to this mansion to gather information regarding Kibutsuji Muzan.
Matters concerning the demon king, who rarely showed himself, would normally be handled by the Hashira.
Yet this case involved many high-ranking officials in Tokyo, including army and navy leaders, making it unsuitable for the Hashira to intervene directly.
There was also the grim reality that if the Hashira were compromised during infiltration, it could expose critical secrets of the Corps. The stakes for them were far higher than for a regular demon slayer like Murata.
And then, there was Murata himself.
He was a survivor above all else, a Demon Slayer who had endured countless missions and even attacks by Lower Moon demons. Entire squads could fall while he alone survived, simply because his presence was so inconspicuous.
Being unremarkable made him perfect for undercover work. He had no choice but to accept this assignment.
The reason he, rather than the specialized "Stealth" units, was chosen was simple: Murata was still a Corps member. He could use breathing techniques if a demon appeared.
Besides, his master suspected something unusual.
Kibutsuji Muzan was an exceptionally cautious demon. In all his centuries-long confrontations with the Demon Slayer Corps, he had never launched an attack against government officials.
Muzan's caution and fear ensured that no demon under his command would strike high-ranking officials without his permission.
Yet this time, not only was his usual restraint violated, Muzan's own name had been dragged into the incident.
This was highly suspicious.
The mission promised to be light on combat. After completing their own duties, the Hashira would arrive promptly, ready to support Murata if necessary.
Yes, there was nothing to fear.
Girding himself with this thought, Murata adjusted his stance and began another day as a servant.
"Hey, newbie, go clean the restroom!"
Upon arriving at his station, Murata received a classic "rookie task."
Though he wore a grim expression, he dutifully carried it out. As he passed the foreman, he discreetly sprayed something on his shoes.
The foreman noticed the faint purple stain on his footwear and scuffed it off irritably. Hidden around the corner, Murata allowed himself a subtle, satisfied smile.
Twelve hours later
Night fell, and Murata stared at his simple dinner of dried fish, pickles, and rice. His body ached from the day's work, and he let out a deep sigh.
Serving others was not an easy life.
Still, it was better than fighting bloodthirsty demons, and he resolved to continue.
Two days passed in this quiet routine.
Murata worked diligently to uncover clues, using a perfume crafted from wisteria flowers.
He tried to discreetly spritz it on everyone he met.
Demons abhor wisteria, much like frogs instinctively fear snakes.
Yet wisteria alone could not kill them. It could inhibit regeneration but never fully eliminate a demon.
Murata's method was simple, but effective. In two days, he had checked nearly ninety percent of the mansion's occupants.
The remaining few, however, were more difficult to approach.
Major Kuroda and his wife could be discounted they were seen outside at noon. Demons could not endure sunlight; this limitation applied even to Upper Moon demons and Muzan himself.
If a demon could survive the sun, the Demon Slayer Corps would have no hope of defeating it.
This left only two individuals unaccounted for: the new maid, Zero Yuko, and Kuroda's daughter, Yumiko.
Neither had been seen outdoors in sunlight. While the official reasons were plausible Yumiko was frail, and Zero Yuko had her duties Murata sensed subtle inconsistencies.
By simple elimination, these two stood out.
Murata could not enter Yumiko's room any intrusion would almost certainly end in his death.
He wrestled with how to proceed, until an unexpected incident occurred that evening.
"Ah!"
A piercing scream echoed through the mansion. Servants rushed to the rear courtyard to witness a gruesome scene.
Yumiko lay unconscious on the white sand, her face pale in the dim sunlight.
Before her was a mutilated corpse, half-devoured and chaotic.
Murata recognized it instantly it was Inuta, the butler who had sent him to clean the restroom on the first day.
The wounds were savage, reminiscent of a large carnivore, the head partially consumed. There was no doubt this was the work of a demon.
A cold sweat broke out across Murata's back. To remain undercover, he had hidden his Nichirin blade in the garden's artificial rock. Without it, he felt exposed and vulnerable.
Fortunately, it was dusk. Even faint sunlight was enough to discourage demons from hunting.
Murata's eyes swept across the crowd. Almost everyone had been accounted for. The only absentee was the maid, Zero Yuko, confirming nearly one hundred percent suspicion.
Yumiko, lying in the sun, could not be a demon.
Murata's first instinct was to contact the Demon Slayer Corps.
But he quickly dismissed the thought.
First, he could only send messages via the Kasugai Crow, which would arrive later.
Second, he could not simply watch a demon begin slaughtering indiscriminately.
Zero Yuko had been identified as a demon. Murata could not stand by.
Clenching his fists, he steeled himself. But his resolve was interrupted by an angry roar.
"You wretched creature! Find out who did this! If I learn which scoundrel plotted against me, I will tear them to pieces!"
Major Kuroda, bloodshot-eyed, held his daughter and swung his ceremonial sword. No one doubted that he might act on instinct.
Murata shrank back, a strange realization forming sometimes humans could be even more terrifying than demons.
Night fell.
Carefully bypassing the guards, Murata retrieved his hidden Nichirin blade from the artificial rock.
Moonlight gleamed off the blackened blade. His talent as a demon slayer was unremarkable, but this did not matter. Most slayers undertaking such dangerous missions carried tragic pasts and vendettas against demons.
Murata adjusted his composure, secured his blade, and returned to his room.
He would not act at night that was a fool's choice. Striking when the enemy was unaware required patience and strategy.
And when was a better time than sunrise, when sunlight itself would weaken demons?
Murata endured the night with caution. At first light, he moved quietly through the Kuroda mansion.
Although security had been heightened after the previous incident, Murata's familiarity with the mansion made this manageable.
He approached Zero Yuko's room, gripped his Nichirin blade, and flung open the sliding door.
A white figure lunged at him.
Without hesitation, Murata activated his breathing technique. Muscles tensed and released with precise control, and the blade struck.
The girl's head separated from her body, falling to the floor.
Murata froze as blood pooled around him.
In the rising sunlight, the body did not burn. The skin showed no scorch marks from the Nichirin blade.
This confirmed a terrifying truth.
Before he could fully comprehend, footsteps and raised guns surrounded him.
"You vile monster!"
Before he could speak, an enraged Major Kuroda struck him in the temple. Pain surged as darkness overtook his vision.
What… have I done?
Had he just killed a human, not a demon?