Chapter Text
Anger was the rice in her stomach, nourishing her. Padding her thin waistline against the starvation of grief, and the ongoing pestilence of demons. Shinobu had been eating from the feast of her anger for so long that she couldn’t remember the flavor of anything else.
Maybe that was the reason for this intoxication. This burned down the back of her throat like cheap sake, as tears stippled along her thick lashes. She’d gone so long on this horrific diet, she’d forgotten that it often was married with passion. Passion for her purpose. Like water flowing, calling her.
Usually that purpose was rife with judgement and justice. A calling to cull the world of humans gone astray. Of souls who abandoned purity to become agents of death and sour sin.
Yet here she was. Throat irritatingly dry within the heated walls of Oyakata-sama’s home. Forehead sweaty and pressed against the tatami, her fingers outstretched in perfect obedience at either side of her tiny, but beautiful face. In front of her, she put her sword on the floor in perfect submission. The sword was a hairpin, a needle, delicate and demure as she was, but also dangerous against her enemies.
Somewhere along the wall, a light bulb flickered. As if it were giving a warning. Darkness was coming.
Shinobu Kocho, Insect Hashira of the Demon Slayer Corps, tried not to notice the woman kneeling nearby. Not a woman, but a demon.
Blinking, but looking at nothing, Shinobu listened.
“My child,” Oyakata-sama’s voice was rich and soothing. A splash of sweetness in her bitter diet. If her anger was hunger, he was the man who led her to the table for breakfast, lunch, and dinner. “Tamayo-san is not an enemy.”
Shinobu blinked again, resisting the urge to tense. To show emotion. To disagree.
It was one thing to have Nezuko with them, a girl forcibly turned who’d never tasted a drop of human blood.
This beast was a whole different matter.
It was as if her daily meal of anger was right before her, but poisoned. Rice spotted with mold. Improperly prepared fugu.
“Yes, Oyakata-sama,” Shinobu said. Perfectly sweet. Masking all the intensity building up in her blood. It was almost unbearable. But if there was one thing Shinobu Kocho was good at, it was the ability to present an unwaveringly pleasant front. A pretty face. Sweetness that hid just how twisted her insides were from the daily consumption of anger. She was certain that if anyone cut her open, they would only find centipedes and maggots in her writhing, bloody insides.
Her pale eyes had no wrinkles from frowning or scowling. Her little mouth was always perfectly and politely held in an almost neutral smile.
Of course, this was a lie.
Beneath her soft skin was a girl no longer fit for the world. A girl who’d watched her parents consumed by this evil before her eyes. Their guts slipping between serrated teeth, while the sentient monsters teased her and her sister about being a precious dessert. She remembered being compared to an ayashirabe cake. Perfectly smooth and pale on the outside, with a peachy cream on the inside.
The demon couldn’t wait to taste her.
She’d grown from a girl to a young woman who understood the horrors of the world too soon. A young woman who adored her older sister and marveled at the miracle that Kanae didn’t burn with the same hunger for anger.
The anger was there. Of course, it was. They’d come into this together. Agreeing to fight evil. To avenge their parents. To make the world right and soothe away this horrible feeling in Shinobu’s gut. But where Shinobu grew intolerant of other emotions, her sister had blossomed like the beautiful Tsubaki flowers she tended every year.
But then Kanae had died.
Shinobu wished her sister had died of something else. Anything else. Plague, childbirth, old age… It was a horrible wish, but Shinobu was sick to death of the anger.
She lifted her head from the tatami, wiping away memories of her sister’s stomach, ripped open like a sacrificial cow. Ignoring the crawling sensation of a demon right next to her. Focusing, like a good girl, like a trained pet, on the hand that fed her.
“With Tamayo-san’s help, I hope you will produce an antidote to Kibutsuji’s blood.”
“A way to turn that darling Kamado girl back?” Shinobu made her voice sound airy, perfect. Only every single breath strangled at the back of her tongue. Itching and dry. Don’t show it. Not now. Not yet.
“Yes, and…” Kagaya Ubuyashiki gave a small, knowing smile. “Anything that might help end this.”
Shinobu nodded as if she understood this command. On the one hand, yes. Systematically destroying demonic flesh with poisons was one of her specialties. Something she learned from devouring texts from previous demon slayers. There was a prominent volume she’d read as a child, shortly after she and her sister arrived at Himejima-sama’s house to join the slayers. The taciturn man couldn’t read because of his disability, but he had insisted on a proper continuation of education for the two girls who nearly bullied him into accepting them. Their hired teacher was a waif-like man who ran the infirmary at the Butterfly Mansion. Hideo-san was the one who taught her medicine, and when he passed away shortly before her 14th birthday, he’d agreed to recommend her for an apprenticeship in the skills of a doctor.
The first ‘grown-up’ book she’d ever read was written by the first water hashira of the Demon Slayer Corps. A man who’d previously worked as an apothecary. From what Shinobu understood, Kiyomizu Kira experimented with making concentrations of wisteria as wards. Though his purposes were less grand than Shinobu’s work. He’d mostly added Wisteria essence to pesticides of citrus already in use during the Sengoku Era.
She expanded upon that, took the idea of warding away demons, and opted for the offense. Coating her blade and sharpening the bite. She experimented with pastes over the blade, oil-based coating, beveling, dipping into toxin after toxin…
Shinobu needed good teeth for her diet, and she knew it.
“As you wish, Oyakata-sama.” She bowed again. Perfect. Polite. Lying about her comfort, or lack thereof, with every practiced movement. Then she turned, skin stippling with the movement. With the way she had to force herself not to attack or run, when she finally looked at the demon full on.
It was disgustingly unfair how beautiful Tamayo was.
Shinobu had hunted enough demons to know that they didn’t always end up appearing like monsters. Some of them looked quite normal until their bloodlust dictated their actions. Those who could mask their abominable nature behind an air of normalcy were the worst ones. Inevitably evil. Gratingly intense and horrific.
Tamayo’s skin was smooth and pale, not a single mark of age or sickness. She wore her dark hair up sensibly. Her kimono was a perfect shroud of floral silk over her petite body. And her eyes, those eyes peering at Shinobu with hidden thoughts, possibly a predator’s intentions, they were… the color of wisteria petals.
The hair on the back of Shinobu’s neck stood on end. A natural prey response, but… but Shinobu was the type of woman to turn the tables. To fight. To overcome.
Her gaze fell over Tamayo’s delicate jawline, down the smooth, pale column of her neck.
She must have been beautiful as a human. A true catch for her time… however long ago that was.
The saliva in Shinobu’s mouth gummed up with a mix of distaste and… and something else. Flicking her gaze back up to the demon’s face, she refused to bow this time. Halting an action as natural and ingrained as breathing.
It was a slight, a quiet protest.
Would she work with this demon? Yes, Oyakata-sama decreed it so. Therefore, she must. Did she have to show this demon the same respect she’d show a human? Absolutely not.
“Oni. My home is not a playground. There will be rules while you are there.” Shinobu let her voice be friendly and soft, as if they were discussing what desserts to have at tea, and not a set of hard boundaries she expected this thing to follow.
The demon simply gave a small nod.
“Understood.”
Her voice was smooth, beautiful. Almost intoxicating. It was immediately disarming, immediately soothing. Only Shinobu struggled against that, stiffening her back as if the one-word response had been a slur on her words.
“During the day, you will stay in the room I give you. No wandering.” Her voice was tighter with this command, fueled by the discontent churning in her stomach. “The mansion is a ward. There are many windows to facilitate airflow for the protection and healing of our patients.”
“I require little rest. Are there ways I can work during the daylight hours?”
“I will have a desk set up in the room. It is big enough for you…” At this, Shinobu was interrupted with a slight cough. Her senses zoned in on it, identifying it as Kagaya Ubuyashiki. Though the soft sound seemed more like a polite intrusion and not like the gurgling rasp of his typical sickness. And indeed, when Shinobu turned to him, he gave her a slight, beatific smile.
“Our friend Tamayo needs a space big enough for two people, my child. The west wing, if you please.”
Shinobu broke down in cold shivers despite the artificial heat of the room. In the muddling miasma of her anger, she became aware as out of thin air, a wavering figure appeared, increasing in clarity and form… like a spirit born out of smoke.
Another demon.
Young.
Male.
With an equally human appearance, and a deeply troubled look on his face. It looked as if he’d been biting his lower lip with consternation the entire time Shinobu spoke. His pale hands were clenching bunches of his navy blue hakama, in apparent self-restraint.
“This is Yushiro,” Tamayo said, as if concealing another demon nearby wasn’t an invasive, horrific act. Disrespectful… suspicious… It deserved immediate scrutiny and judgement, but Oyakata-sama merely laughed as if it were nothing. It must be because he couldn’t see. The disease slowly killing him had stolen his sight, so he didn’t know the other demon had hidden itself. Or had he?
“No.” Shinobu’s features cracked. “No.” The only defiance she’d give. Not an explanation. Not a yell. Completely in control, polite, a perfect woman.
But her defiance was nothing. It was dust. It was fleeting.
And Kagaya Ubuyashiki knew this.
*
Tension filled the following days at the Butterfly Mansion. As if the foundations of the buildings knew a tainted duo lived on the grounds. As if the very essence of demon blood were soaking into the floor and choking the hallways with sickness.
It was entirely possible that every attendant, from Shinobu’s sweet adopted sisters to the resident kakushi and their trainees, whispered about Shinobu’s stony silence. About the sudden closure of the west wing. The three patient rooms of the west wing, the small Shinto shrine, and the library were blocked with paper wards and pretty calligraphy scrawled on a sign at the front door. Stay out. Calligraphy that could only be the work of Shinobu Kocho, Insect Hashira, and a woman whose rage was so thinly veiled behind her pleasant face.
I wonder what’s going on…
I heard Kocho isn’t allowed to take part in Hashira Training… Do you think she’s being demoted?
There are strange noises coming from the west wing.
Have you seen the cat that keeps coming around? Do you think it’s one of Himejima-sama’s?
There’s a patient in the west wing whose disease is so severe they are worried it will wipe out the whole corps…
Oh, no… is it the Spanish flu again?
Shinobu walked by the gossip, head held high. Engrossed, not in her work as she usually would be. Instead, it was as if her mouth was salivating without her permission, with the hunger of anger popping in her stomach.
All she could see every time she closed her eyes was Tamayo’s face. Her ears rang with the cloying sound of her voice.
Kocho-san, I have finished reading your research notes. Please allow me to help with…
Good evening, Kocho-san. I’ve purified the newest concentration of Wisteria Poison. The measurements have an increased concentration of 2%.
Kocho-san, have you thought about recrystallization as a method of concentration?
Tamayo was enviably intelligent. Beautiful. Perfectly poised when Shinobu felt like her own blood was going to boil over until she grabbed the piping tools and forced these new concentrations down this infuriatingly soft demon’s throat.
Maybe it would be good to watch her skin blotch up, boils and sores destroying the pretty illusion… and give Shinobu the breath of relief she needed upon seeing the truth of how ugly this monster really was.
Her fingers trembled as she felt along the polished wood of the west wing door. Gaze darting around to make sure no one followed her. She’d caught one of the triplets, Sumi, watching from a bush the other day. The poor little girl was deathly worried and cried big tears when Shinobu confronted her.
Please, Oneesan, please wear a mask! The little girl had trembled and cried and held out one of the hospital masks. I’m so afraid you’ll become ill.
You are so sweet, Sumi. I’ll be careful, I promise. She took the mask from the girl, patted her on the head with reassurances that nothing was wrong. Nothing at all…
That was several days ago, and today there was another girl hiding in the bushes. Though Kanao didn’t seem to wait for Shinobu. The teenager, the first of her adopted sisters, pretty and calm, was standing on her tiptoes trying to peek into the windows. It was an unusual act of curiosity. Kanao was not the type to sneak around, but… but Shinobu supposed she understood.
After all, the air around the west wing seemed different. Heavier. It was winter, and yet… it reeked of sun-heated flowers.
And the Flower Breather was mere steps away from promotion, her senses attuned to demons in a way that few in the corps ever managed. Shinobu sometimes wondered if this perception was a feature of Flower Breathing, or if both Kanae and Kanao were simply more situationally aware than Shinobu was.
It didn’t bother her, per se, to know that both her older biological sister and her younger adopted one were so strong in respective ways that Shinobu could never match. It didn’t bother her because Kanae, so sweet and lovely, had a habit of praising Shinobu.
You’re the smartest person I know.
You are a genius, Shinobu…
There was no competition, no jealousy. Just a blanket of acceptance. Their strengths complemented each other. Shinobu had grown into the person she was in part because of the value and love in her life. Traits of goodness that trickled into her relationship with her adopted sisters. Traits that allowed her empathy and understanding when treating slayers.
Traits she desperately hoped would cover the hunger for vengeance that soured her soul.
So she wasn’t bothered. She wasn’t jealous that Kanao was sneaking around, having somehow sensed the demons living within their midst. She was, however, slightly vexed by it.
Oyakata-sama had stressed the need for secrecy, for subtly in having the demons with them.
It would do no good for this boon to become the talk of the corps. Kibutsuji needs to be caught unaware, and if he knows she is here before we are ready, we might as well forward him all of our battle plans, ne?
Straightening her spine, Shinobu cleared her throat lightly. It was just enough for the slightly younger girl to jump where she stood, and look over at her with wide eyes.
“Gomen, Shinobu-san.” No denying what she was doing. Just a simple apology, and a soft bow that dipped the inky black of her ponytail over the white cape she wore. But… she didn’t run off or back down. Staying there and waiting silently for Shinobu to explain what was going on.
She supposed if anyone was safe to tell about the demons in their home; it was Kanao. The perfectly discrete girl who would never once loosen her lips to spread gossip. Yes, this might be alright.
With a sigh, Shinobu gave the younger girl a soft smile.
“You’re curious?”
Kanao didn’t speak, just gave a brief nod of her head. Shinobu let her gaze slide to the door. Her fingers trailed along the wood once more. The tips of her fingers thrummed, almost as if she could feel the blood pulsing out of the sharp need to rip it open, tear down the walls and purify the insides with the light of the cold winter sun.
“I trust you will not rest until I tell you why there are demons in the west wing?”
“I thought it was Nezuko-chan at first, but Aoi-chan has been trying to have her help in the kitchen all day. This feeling is too far away to be Nezuko-chan.” Kanao said dutifully.
“I see,” Shinobu said, and pulled open the door to the west wing. “There’s nothing to be done then. Come with me.”
The darkness of the west wing greeted them. Their intellectual forefathers built this section of the Butterfly Mansion without windows. Without natural light. It was only good for a few things. Illnesses that brought light sensitivity, like when Shinazugawa-san suffered from migraines, were treated here. When the Spanish flu was ravaging the country, slayers who went into the bigger cities came here to quarantine after their assignments finished. It was necessary and went a long way in quelling outbreaks, though the disease had been so infectious any attempts at containing and stopping the spread felt dauntingly ineffective.
Historically, they built the west wing to house a corps member who was forcibly turned into a demon. Records suggest that someone tried to find a cure for this unnamed man, but no writings helped Shinobu understand the method or trials used. The only thing she could find was a short annotation signed by an Akimitsu Ubuyashiki saying that the man turned demon could not be recovered.
She figured he had put down the soul before it could cause problems. Possibly the only way to save a demon’s soul… to cull them before they sipped their first blood. The Shinto shrine at the end of the west wing was likely where the man’s ashes were. Inside the confines of an old sword sheath, painted over with a crackling red lacquer and golden chrysanthemums. From the death relic, Shinobu knew a secret she would take to the grave with her rather than dishonor any friend of hers.
The man they’d been unable to save was a Rengoku. As far as she knew, the only one who was not interned in their family crypt... alone, here, after having been turned. She liked to think it was bravely refused, and that it was a mission gone bad.
She reminded herself every single time she went demon hunting that there were no guarantees. They could all die. They could face being turned forcibly, and if that happened, the only honorable thing to do was beg for a cure, or throw themselves into the sun.
Shinobu waited until Kanao stepped inside the door, and then slid it shut, flipping a latch to lock it behind them. The electric lights in the hallway glowed a soft yellow, just enough that walking wasn’t a hassle. Though, as Shinobu kicked off her shoes, and waited for Kanao to remove her heavy boots, she focused on the sound rather than the sight. She focused on the near peaceful quiet. There was the ticking of a grandfather clock near the doorway, a decoration brought to the west wing from an older doctor who’d retired when Shinobu was still a child. Distantly, she could hear the slight meow of a cat. The same pretty little calico who kept finding its way all over the Butterfly Mansion, getting picked up and petted by delighted visitors.
It was the demon’s cat. Tamayo and Yushiro, and though there was nothing unusual about it other than a blood demon art had cursed it, Shinobu disliked it wandering everywhere.
The last time she’d seen it, Shinobu had the distinct feeling that the cat was watching her. And the almost insane thought that it was reporting her movements back to the demons.
Shinobu was about to tell Kanao not to leave her sword at the door when she heard it. The distinct swoosh of a paper screen sliding open along the track. Turning to look down the long hallway of the west wing, Shinobu saw her step out of the room. One dainty, perfect step, pale clean feet on the hardwood floor. Tamayo didn’t wear socks inside the house, but Shinobu hadn’t commented on it as speaking any more to the woman than was required made her gut twist in weird directions.
“Good evening, Kocho-san. I see you brought a visitor.” The demon’s voice lulled through her, reverberating something feral through her lungs.
“Good evening, Tamayo.” She returned, squishing everything but her cold politeness aside. Even then, the demon did not deserve that.