Chapter Text
She had seen beautiful temples before.
The Oyakata had a private one surrounded by a large pond full of koi and lily pads.
Naturally, as a demon slayer, when she travelled she had been to many temples herself.
Kyoto’s quiet verandas where incense drifted lazily through the air.
The great wooden stage of Kiyomizu, high above the city, where prayers clung to the wind like paper charms.
In Nikkō, shrines carved so intricately they seemed almost alive, hidden beneath towering cedar trees older than most bloodlines.
She had walked those moss-dark paths alone at dawn, her sandals damp, her blade heavier than usual.
In Kamakura, bronze Buddhas sat in eternal meditation while she tracked something that had been feeding behind the prayer halls.
In the mountains of Nagano, she had slept beneath temple eaves while monks chanted through the night, a comfort against what moved in the forests beyond.
And in Hiroshima, where the great torii stood out upon the water as if floating, she had once watched the tide rise crimson at sunset, wondering briefly how many demons had walked those same shores unseen.
She had seen beauty.
But beauty had never meant safety.
So it was certainly confusing to find this particular temple hidden deep in the Northern mountains.
This was the temple, right? The one Yae's dog had found by chance.
The one supposedly ruled by a demon.
Shinobu adjusted her kasa and pulled her haori closer around her shoulders, breath faintly visible in the brittle air.
It seemed to be a lord’s palace more than a temple.
Stone steps carved directly into the mountainside led upward in wide, immaculate tiers, not worn by pilgrims but maintained.
Scrubbed.
Cleared of snow.
Lantern posts lined the ascent, each capped in bronze, their glass panes pristine despite the wind that howled through the pines.
The outer gates rose tall and shining in deep vermilion, their beams thick enough to withstand siege.
Not the modest wood of rural worship, but timber hauled, shaped, and polished by money.
Too much money.
Beyond the gate, rooftops layered upon rooftops. Sweeping eaves edged in gold leaf that caught the pale winter light.
The tiles were new. Uncracked.
The sort of roofing one would expect in Kyoto estates, not buried in the northern mountains.
And the silence.
No pilgrims. No chanting drifting through the cold air.
No smell of incense.
Only the distant caw of crows and the crunch of frost beneath her sandals.
The compound sprawled wider than expected. Multiple wings branching outward like a feudal manor.
Enclosed corridors connected halls, preventing exposure to the biting wind at least from what she could surmise.
Whoever built this had considered comfort.
A courtyard opened at the centre, shockingly grand, with a frozen pond ringed by stone lanterns.
Even beneath a thin crust of ice she could see koi moving sluggishly below the surface.
Fed through winter. Maintained.
A temple sustained by devotion should not look this… prosperous. Shinobu’s fingers brushed lightly against the hidden vial at her waist. An Upper Rank posing as a monk. Her smile remained gentle, almost amused. “Well,” she murmured softly to herself, stepping through the gate, “how extravagant.”
The air felt wrong.
She swallowed thickly.
Nonetheless, she pressed forward.
There were too many ways this could go wrong.
If Muzan himself was here, he could kill her before she even opened her mouth.
A flick of irritation, a pulse of flesh, and she would be nothing more than scattered cells on wooden floors.
But if the information she carried was true… he might hesitate.
Shinobu stepped through the final gate.
The air inside the compound was warmer than it should have been. Not by much. Just enough to defy the mountain wind clawing at the outer walls.
The warmth felt artificial. Maintained. Controlled.
She was confident he could not turn her into a demon if that was what he chose.
Not easily.
Her bloodstream was already prepared, layered carefully over years with measured exposures and counteragents. If he tried, it would not take root cleanly. That knowledge somewhat calmed her.
Still, confidence was not immunity.
She was walking into the domain of a being over a thousand years old. A creature who had studied biology before most nations understood sanitation.
A mind that dissected humans like specimens and remembered empires as footnotes.
Her smile settled into place, cool and unthreatening.
If he was here, he would already know she had arrived.
She turned her head to the side.
A woman was sweeping the stone steps, bristles rasping against frost.
The moment she noticed Shinobu, she straightened, expression hardening.
“No drifters permitted. State your business and leave.”
Shinobu inclined her head, serene as ever.
“I have come to enquire regarding a position. I understand there was word sent out for someone specialising in compounding medicine.”
Silence followed. The woman’s eyes narrowed slowly.
“You’re a female,” she said flatly.
Shinobu felt her jaw tighten, but her smile did not falter.
“Indeed. One of the fortunate few afforded formal study. I graduated from Tokyo Women’s Medical School and completed advanced pharmacological studies in synthesis.”
Not entirely false. The Oyakata maintained discreet agreements with certain academic institutions, ensuring the Corps received educational materials and private tutoring for its medical teams within the Kakushi. With Total Concentration Breathing, the mind absorbed information at an accelerated pace. Retention became instinct.
The woman stared as if she had begun reciting foreign scripture. “You look very young.”
“Small stature,” Shinobu replied quickly, adjusting her gloves. “I am twenty-five.”
A lie.
She was barely twenty. But twenty would sound like a girl. Twenty-five sounded like someone men might reluctantly tolerate. The woman’s gaze lingered on her medical case.
“And you believe monks in the northern mountains require the services of a university-trained physician? A woman at that?”
Shinobu’s eyes softened just slightly. “I believe,” she said gently, “that when a body resists conventional treatment, pride becomes expensive.”
That did it. A flicker. Brief. Subtle.
The woman’s sweeping slowed.
“Wait here,” she said at last.
Shinobu watched her ascend the steps. The gates did not open immediately. But they did not close, either. Which meant someone inside was listening.
It took five minutes for her to return. There were two men beside her, more guards than pilgrims or worshippers. One approached and bowed. Shinobu knew instantly he was a demon. The cloud cover was thick enough to grant him freedom, though he kept himself carefully shaded. She offered no sign she understood.
However, the demon seemed far more amiable than the woman sweeping the steps.
“Greetings. My name is Tamio Enmu. And yours, miss?”
Shinobu licked her lips lightly trying to not react to the sultry tone in his voice.
“Kocho. Kocho Shizuka.”
The name settled between them.
Enmu paused.
Shinobu resisted the urge to smile.
The Kocho name still carried meaning in certain academic circles.
Her parents had been known in pharmaceutical research before their deaths. Her father had earned his medical degree in Berlin, publishing under German supervision. Her mother had graduated from Tokyo Women’s Medical School and assisted in compounding clinical sedatives. They had never been demon slayers. Just physicians. Until they weren’t.
“A Kocho?” Enmu hummed softly. “How nostalgic. I recall several publications… something regarding dementia praecox, was it not? Or was it a paper on hypnotic sedation in cases of hysteria?”
Shinobu cocked her head, just enough. “My father’s work concerned regenerative neural degeneration and the instability of suggestible states,” she replied smoothly. “He argued that what was termed ‘mind-splitting disease’ was less a fracture and more a misfiring of internal regulation.” Enmu’s smile widened.
“How progressive.”
“He believed certain compounds could quiet the overstimulation without dulling cognition entirely. Bromide derivations were inelegant. Chloral hydrate too crude. He was working on plant-based alkaloid modulation.”
Enmu’s eyes narrowed.
Now he was interested.
Hypnosis. Sedation. Suggestibility.
This was not the language of a shrine herbalist.
This was the language of someone educated.
“And what became of his research?” Enmu asked, concealing the excitement from his voice.
Shinobu let the faintest shadow pass across her expression. “It ended prematurely.”
Not a lie.
Enmu studied her a moment longer.
“Yes,” he muttered. “Many things do.”
He scrutinised her a bit longer. Not visibly. But Shinobu felt it. The faint stillness behind his eyes. The way his smile held just a second too long. Communication. Silent and distant. With an Upper Moon? Or with Muzan himself? She could not tell.
But when his gaze refocused, something had changed. Approval.
“I see,” Enmu said pleasantly. “Well. Clearly you know what you are speaking of. The last physician who presented himself here still believed in leeching and balancing the humours.” His lips curled faintly.
Well that physician is most likely dead.
“How archaic.” Shinobu inclined her head.
“Medicine that clings to superstition is merely ritual.”
“Quite so.”
He stepped aside and gestured toward the inner courtyard. “Please. Come inside, Kocho-sensei.”
The gates opened with a heavy, loud groan. Shinobu adjusted her kasa once more and stepped forward. The moment she crossed the threshold, the temperature changed. Warmer. Not natural warmth. Contained warmth. As though the mountain itself had been excluded by decree.
The courtyard sprawled wide and immaculate, snow carefully cleared from the stone paths. Lanterns hung beneath sweeping eaves, their flames unnaturally still despite the wind beyond the walls. Monks and women moved silently between corridors. Too silent. Too synchronized. Their eyes flickered toward her, then away. Watching. Assessing. Cataloguing.
She counted exits instinctively. Left corridor, enclosed walkway, second-floor veranda, rear gate partially obscured by hanging banners. Her breathing remained slow. Even. Total Concentration. Her pulse did not quicken. But her fingers brushed the inner lining of her sleeve. Three vials. One aerosolised. One liquid. One for herself. Just in case.
Enmu walked beside her, hands folded loosely behind his back like a courteous attendant. “You understand,” he said conversationally, “that discretion is essential here.”
“Of course.”
“You will be asked to examine a patient of importance.”
“I assumed as much.”
“And you will refrain from unnecessary questions.”
Shinobu’s smile softened.
“I only require what is relevant to treatment.”
He glanced at her sidelong.
“How disciplined.”
They approached a larger hall at the center of the compound. Unlike the others, this one was guarded. Not ostentatiously. But unmistakably. Two figures stood motionless at either side of the entrance. Not breathing. Not shifting. Demons.
The doors slid open. Warmth spilled outward.
Her heart did not stutter.
But inside, the atmosphere changed. So. It had worked.
Enmu gestured lightly. “After you.”
Shinobu removed her kasa stepped forward.
Into the lion’s den.
She was lead to a room and told to sit and wait.
So sit and wait she did.
It didn’t take long for her to hear the footsteps.
Smooth.
Unhurried.
Confident.
The sound alone made something cold settle at the base of her spine. Power. And not the ornamental kind. Contained. Ancient.
She turned as the doors slid open.
A man stepped inside, dressed impeccably in Western attire — dark coat, tailored waistcoat, gloves fitted perfectly to long fingers. His hair was arranged and parted carefully. He smiled. It was gentle. Almost kind. It did not reach his eyes.
Instinct compelled her to lower her head.
When she raised it again, her suspicions hardened into certainty.
Red eyes. Too red. Too still.
She knew without a doubt she was standing before Kibutsuji Muzan.
The demon king studied her in silence. “So,” he said at last.
“You have travelled quite far to reach a remote temple.”
Not a greeting. An assessment.
Shinobu folded her hands before her respectfully.
“I was informed there may be work suited to my expertise.”
“And what expertise would that be?”
“Compounding medicine. Pathological analysis. Pharmacological synthesis.”
His gaze did not blink. “You presume we require such services?”
There it was.
The trap.
She bowed her head slightly again, just enough to appear deferential. “I presume nothing. I follow opportunity.”
His expression did not change, but the air in the room tightened. “Opportunity,” he repeated. “In a mountain monastery.”
“Yes.”
“And who informed you of this… opportunity?”
She allowed the faintest pause, as though weighing confidentiality. “A courier from my travels mentioned that previous physicians here were… unsatisfactory.” She kept it vague. No mention of illness. Only incompetence.
Muzan’s eyes narrowed a fraction. “And what would you consider unsatisfactory?”
“Outdated methodology,” she replied calmly. “Humour balancing. Leeching. Sedatives without understanding systemic interaction.”
Silence again. He took one step closer. Just one. The movement was controlled enough to appear casual, yet menacing enough to test her composure.
“And you,” he said softly, “believe you possess understanding?”
“I believe,” she answered gently, “in studying something new and drawing a conclusion” That was bold. But not accusatory.
His gaze lingered on her face, searching for something. Fear. Recognition. Reverence. She offered none. Only composure.
After a long moment, his smile returned. “Very well, Kocho Shizuka. You claim skill. I value skill.” He turned as though already finished with her. “You will be evaluated.” Not invited. Not accepted. Evaluated.
“If your knowledge is sufficient, you may remain.”
If not… The rest did not need stating.
She briefly wandered how many physicians Muzan had killed here before her in a rage.
Shinobu inclined her head once more. “Of course.”
As he moved toward the inner chamber, she felt it. A subtle disturbance in the air around him. A faint delay in something that should have been seamless. It was barely perceptible. Almost imagined. But not quite.
Phase one done.
But what did he mean by evaluation?
Shinobu remained sitting where she had been left. She did not fidget. Did not pace. Ten minutes passed in eerie silence, broken only by the distant murmur of wind against the outer walls. Then the shoji doors slid open again. This time, the atmosphere shifted differently. Not compressed. But… effervescent.
Another demon entered. And Shinobu knew instantly, this was an Upper Rank.
It radiated from him. Not just power, but presence. A confidence that bordered on playful arrogance.
He was tall, draped in layered robes far more ornate than the others she had seen. Long silver-blond hair spilled over his shoulders like spun silk. And his eyes— Chrome. Multicoloured. Reflective. Almost crystalline.
They were beautiful. They were wrong.
He beamed at her. Wide. Delighted.
“Oh my,” he said cheerfully, warm and bright as though greeting an old friend. “A guest.”
He clasped his hands together in soft applause. “How delightful. We so rarely receive visitors of… professional distinction.” Shinobu lowered her head politely. “Kocho Shizuka.” He stepped closer, far closer than necessary, tilting his head as he studied her face openly.
“Kocho,” he repeated with obvious pleasure. “How nostalgic.”
His gaze drifted to her medical case. “A doctor. And a lady at that. How refreshing. The last one who graced our halls fainted at the sight of a surgical incision.”
His smile widened. “I do hope you are made of sterner stuff.”
Shinobu’s lips curved faintly.
“I assure you, I do not faint easily.”
“Oh, wonderful.” He extended a hand in mock ceremony. “I am Douma. I oversee this temple.”
Not abbot. Not monk. Oversee.
“As you can imagine,” he continued breezily, “it is such a burden managing so many… followers. Bodies are so fragile, aren’t they? They deteriorate. They behave unpredictably.”
His gaze flicked back to hers. “We require someone with insight.” There it was. Carefully phrased. Still no admission of anything specific. He leaned slightly closer.
“And it is particularly delightful that you are a woman. A change of atmosphere is always welcome. New perspectives. New hands. New ideas.” His smile did not waver. “But first,” he added brightly, straightening, “we must see whether you are as competent as you claim.”
Ah. Evaluation.
He gestured toward the inner corridor.
“Come. Let us begin.” He turned without waiting for her. Shinobu followed. Every instinct screamed. This was not a man testing her out of suspicion. He was excited. Curious. Amused.
Douma did not slow as they walked. His steps were slow, almost buoyant, sleeves drifting softly behind him.
“Before we begin,” he said pleasantly, “there are a few small rules.”
Shinobu inclined her head. “Of course.”
“You may see… unusual things here.”
He glanced at her over his shoulder, chrome eyes gleaming faintly.
“This is, after all, a place of spiritual transformation.” The word lingered. “You are not to ask questions about what you witness. You are not to concern yourself with matters beyond your assigned task.”
His tone remained cheerful. “You will focus only on your patient.”
Shinobu nodded once.
“And if the constitution of this patient is… atypical?”
Douma’s smile widened.
“How perceptive. Yes. Atypical is a very polite way to describe it.”
He turned fully to face her now.
“Our patient is of an unnatural constitution.”
There it was. Subtle. Carefully phrased. Not human. Not entirely.
Shinobu allowed no reaction. “I specialise in irregular pathology,” she replied evenly.
“Splendid!” He clasped his hands together. “One more thing.”
His expression softened, almost sympathetically. “There is no screaming here.”
The words were delivered gently. “As you may hear sounds that are… distressing. I find that emotional outbursts disrupt the peace.”
You mean the screams of demons eating humans.
His eyes studied her carefully now. “If you are easily disturbed, I would prefer to know before we proceed.”
“I am not,” she answered calmly. “Wonderful.”
He resumed walking, then stopped once more at the threshold of a larger corridor. “Oh. And of course.” He turned his head towards her, studying her with a look that might almost be mistaken for kindness. “I am, quite a considerate host.”
The grin on his face was sinister.
“You have an opportunity to walk away.” Silence settled between them. “If you accept this position, you will remain within the temple grounds for the duration of your employment.” A pause “Those who accept do not leave until the Master is satisfied.”
Not a threat. A fact.
She doubted any of the previous ones had left.
Shinobu met his gaze steadily. In that moment, she understood. This was not merely about evaluation. This was containment. If she stepped forward now, she would be entering a gilded cage. Bu she didn't think he intended to let her free either.
She smiled. “I assumed as much.”
Douma’s expression brightened instantly. “Oh, excellent.”
He slid the door open. “Then let us not waste any more time, Kocho-sensei. You are a sensible woman indeed. Most ask about the pay.”
Shinobu’s smile did not move. “Compensation is important,” she replied breezily, “but as a scientist, I am far more interested in anomalies.”
Douma beamed at her, delighted. “So is our Master! He is something of a scientist himself!”
More like a parasite and a blight upon humanity, she thought coolly.
“Oh?” she asked instead.
“Was that the gentleman I met earlier? He did not offer his name. How should I refer to him?”
Douma gestured lazily to one of the temple attendants, who bowed and scurried ahead to prepare the chamber further as they continued down the corridor. “Tsukihiko Higenbana.”
Shinobu gave no outward reaction as the name sunk in, in all its familiar glory. So that was the identity he wore here. Higenbana.
The name of one of Japan’s largest pharmaceutical enterprises. Its public owner, if she recalled correctly, was a woman. Rei Higenbana. Interesting.
Her thoughts circled.
Tanjiro had once described seeing Muzan walking through Asakusa beside a woman and child, playing the role of husband and father. Was this another mask? Or was the corporation the mask? Douma continued speaking, oblivious.
“Our Master believes medicine should advance beyond the crude traditions of the past. He appreciates innovation.” Of course he does, Shinobu thought.
He has spent a thousand years trying to perfect his own biology.
“And he is very particular,” Douma added, glancing sideways at her. “He dislikes incompetence.”
“I would expect nothing less,” she answered smoothly. They turned another corner. The architecture changed subtly here. Fewer lights. Heavier doors. Thicker walls. The temperature dropped.
Douma stopped before a set of reinforced sliding panels. “You see,” he said lightly, “our Master values progress. He built his enterprise from nothing. A visionary.” A pause. “He does not tolerate those who impede it.”
His smile remained radiant.
“Which is why this case is… of interest.” There it was. Not illness. Not injury. A case.
Shinobu adjusted her form.
“And how long has this case been under observation?” Douma’s eyes flickered, just slightly. “Several months.”
Now that was intriguing.
“Has there been deterioration?” Another small flicker. “Regenerative inconsistency.”
Her pulse remained steady. Regenerative inconsistency. That was not something demons experienced naturally.
Interesting.
She inclined her head.
“I will require proximity.”
“Of course.”
“And access to the full presentation. Concealment complicates assessment.”
Douma laughed softly. “Oh, you are bold.”
He slid the door open.
Cool air spilled outward. And beneath it...something ancient. And wrong.
“Welcome,” Douma said gently, stepping aside. “To your anomaly.”
Shinobu said nothing, keeping herself every bit the itinerant physician summoned for a peculiar case. Because lying before her, on a Western-style hospital bed set incongruously within the temple’s polished chamber, was a demon. Another Upper Rank.
IV lines threaded into his arms. A slow drip of clear solution feeding into veins that should not require such assistance. An oxygen mask rested over his face. “He was born deformed with six eyes,” Douma said cheerfully. “Try to ignore it. Most of the worshippers believe him blessed.”
Shinobu did not react. Blessed. Yes. Of course they did. Something to explain away than outright claim this was a demon.
Douma’s hand settled onto her shoulder, fingers cool, the gesture deceptively familiar as he leaned in close. “This man is very important,” he murmured pleasantly. “Especially to our Master. He is… invaluable. A business partner of sorts. Not easily replaced.”
She filed that away without comment. Muzan did not care for sentiment. If he valued this demon, it was because he was irreplaceable. Something had compromised a critical asset. Shinobu stepped forward, subtly easing Douma’s hand away as she approached the bed.
She resisted the urge to dust off her shoulder as if something filthy had brushed.
And then she truly looked.
The first thing she noticed was not the six eyes. It was the wasting.
The musculature was diminished. Not dramatically, but unmistakably. The sharp planes of his face had grown hollow. Skin clung too closely to bone. The natural density demons carried... that unnatural vitality, was reduced.
He resembled a human coma patient.
Or someone in the late stages of consumption.
Except demons did not deteriorate this way.
Even starved demons did not waste.
They grew violent. Frenzied. Desperate.
They did not thin gradually or if they did it was only to a certain extent. Starvation could technically kill them, but over years of eating absolutely nothing.
She placed two fingers lightly against his wrist. The skin was cool. Regeneration pulsed beneath it then faltered. Resumed. Stuttered. It was subtle. But wrong.
She glanced to the IV line. The fluid was clear, likely glucose or saline analogue. Though she suspected it might have been some sort of human bodily fluid. “Has he been feeding?” she asked calmly.
A brief pause.
“Yes,” Douma replied. Regular feeding, then. Did they give him human nourishment like blood through the IV instead? So this wasn’t starvation.
“Has there been injury?” she continued, knowing it wouldn’t show, but keeping in character.
“None significant.”
She leaned closer, watching the rise and fall of his chest beneath the oxygen mask. The mask was unnecessary. Unless his body was struggling to utilise what it absorbed. She pressed gently along his sternum, watching for tissue correction. The response lagged. Not absent. Delayed. Hmmmm.
Demons regenerate from template memory. their cells replicate from an internalised ideal structure. If that template becomes unstable… Shinobu withdrew her hand slowly. She did not speculate. Did not offer a conclusion. “When did the symptoms begin?” she asked simply.
Douma smiled. Brilliant. Unbothered.
“In good time,” he said lightly. “In good time.”
He stepped away from the bed as if the matter were trivial. “Medical curiosity is admirable, Kocho-sensei. But we prefer structure here.” Structure. Control….. He gestured toward the corridor.
“For now, you will be provided with accommodations.” She did not argue. Did not press further. That, too, would be noted.
As they walked, Douma’s tone returned to its breezy warmth. “Enmu-san, whom you met earlier — will provide his… medical files and notes.” A soft laugh. “He has taken quite an interest in the case.” Of course he has. Probably ordered to by Muzan. Perhaps Enmu had some scientific expertise himself. She would find out. After all there were demons that posed as medical professionals.
Shinobu had once slayed a demoness that had worked as a midwife, killing select babies after births as her preferred meals.
“Your task,” Douma continued, “is to review the documentation carefully. Develop theories. Conduct assessments when permitted.” Permitted. “Most of the direct care,” he added almost casually, “is overseen by Dr. Enmu.” A faint pause. “And by Higenbana-sama himself.”
That was important.
Muzan was personally involved.
Which meant this was not merely an Upper Rank’s inconvenience. It was something that concerned the progenitor.
They stopped before a smaller sliding door. Douma opened it with a theatrical flourish. The room within was simple but immaculate. A futon neatly arranged. A western desk. Writing implements. A brazier for warmth. Contained. “You will reside here,” he said pleasantly. “It is comfortable. I would not wish our new physician to feel unwelcome.”
Shinobu stepped inside. The doorframe felt narrower than it had from the hall. A subtle narrowing of options. “Your movements within the temple will be… supervised,” Douma added gently. “Merely for safety.” “For whose?” she asked softly. His smile widened.
“How charming.” He stepped back toward the corridor.
“Oh — silly me. I nearly forgot one small detail.”
He leaned back against the doorframe, smiling at her as if sad. That typical demon look before they devoured their prey. How lovely.
“If he dies…” A brief pause before he smiled wide.
“…you will die.”