Chapter Text
The moon hung low on the horizon, full and bright, spilling soft light onto the devastated rubble of the streets. Bodies were scattered on the streets, pale faces frozen into horrified grimaces, pristine and uninjured yet eerily frozen at their most vulnerable.
It was almost peaceful, for a heartbeat, as if a fight had not been raging through those very streets mere moments ago. Giyuu pushed his hair, matted with sweat and grime, out of his forehead, unusually out of breath as he fought to regain his composure.
A few paces beside him was Shinazugawa, and although he did not turn to look, he could hear that he was in a similar state. They had been fighting for hours, after all. Giyuu could not recall the last time a demon had kept him fighting so long that he actually found himself counting the minutes down to sunrise.
This was only Giyuu’s second time fighting a Lower Moon, and while the last one he had encountered with Tanjiro had given him no trouble at all, this one eluded his blade even with another Hashira by his side. Whether being partnered with Shinazugawa, though, whose fighting style was quicker to clash with his own than the enemy’s, was much of an advantage– that remained undecided.
“Tired of all the scurrying, little mice?” a lilting voice floated down from above. The demon– Kuroha, if Giyuu remembered correctly– had perched herself on the top of a streetlamp, eerily similar to an actual cat’s ability to rest atop a tiny space. She was easily within reach of Giyuu’s sword, but he knew by now not to strike blindly. This demon was a master of illusion, after all– too many times he had swung at what seemed like his opponent, only to be parried by a furious Shinazugawa, whom the demon had cast an illusion over to trick him.
Instead, he watched silently, trying to calm his breathing down, trying to think. He had the time– this was a demon who liked playing with her food, not striking down relentlessly.
The beginnings of a strategy were whirling around in Giyuu’s head, but they had yet to condense into something usable. His thoughts were interrupted when, with a sound like fabric tearing, nine silhouettes burst out of the demon’s body and landed on the streets. Nine pairs of golden eyes blinked up at them as the vaguely feline creatures prepared to strike.
“Fucking bastards started multiplying again,” Shinazugawa growled under his breath. Above them, a cloud obscured the moonlight, paradoxically letting Giyuu see the clones better. He struck three of them down as they lunged at him, noting with a raised eyebrow that they did not immediately rematerialize.
“Keep your distance,” he warned Shinazugawa, feeling a tug in his gut warning of impending danger. The Wind Hashira scoffed loudly even in the middle of combat, shooting Giyuu a poisonous glare that he did not turn to meet.
“Don’t tell me what to do, Tomioka.”
A group of Kurohas instantly swarmed Shinazugawa, but they managed nothing more than a slash in his sleeve before they were cut through with strikes as swift as wind. The afterimages seemed to almost waver in the air for a moment before reappearing. As the moonlight flooded back onto the streets and the fight picked up its fevered pace with Shinazugawa at the storm's eye, Giyuu decided to test a theory.
Two of the clones split off from the main fight to attack Giyuu. Instead of fighting back, however, he took off running to the side– leaping off a wall and kicking off as high as he could, launching himself into the air. His haori fluttered behind him in the movement, casting a large shadow over the clones below him. This time, it was more clearly visible how they seemed to glitch out of sight, even if just for a moment.
That was it. The fatal weakness, inevitable for a Lower Moon.
With a strike like a floating dance, Giyuu's blade smoothly cut through the necks of both images. This time, he counted a whole fifteen seconds before they reappeared, this time as one on top of the roof.
“Good eyes, pretty one,” the clone– or perhaps it was the true body– mused, something like a purr in her voice. Her eyes narrowed at Giyuu, much like a predator sizing up its prey. “You aren't nearly fast or big enough to eclipse me, though.”
Before Giyuu could act or even respond to the taunt, the body had vanished, leaving a shimmery haze in its wake.
“Shinazugawa,” he called out, eyes darting around him as he braced for the next attack. His partner grunted, feet skidding in the dirt as he landed from an airborne attack of his own.
“I got it,” he snapped. “She's using the moonlight, isn't she?”
Giyuu made a sound of approval, distantly impressed that he had paid attention even while engrossed in combat of his own. “It would seem so. The mirages need uninterrupted light to stay alive.”
“Then I'll give ‘em a storm,” Shinazugawa grinned, the force of it seeming to split his face. His breathing deepened, his posture tensing, before he twisted his body and swung forward.
“Wind Breathing, Fifth Form: Cold Mountain Wind!”
With the drag of his sword through the air, a roaring gale rose in the streets, tearing through the smoke and dust. The windowpanes nearby shattered, fragments of broken glass misdirecting the light in a million directions while the rest of it was lost in the haze of grit and rubble.
Amidst the chaos, Giyuu's own blade cut streams through the air, methodically striking down every illusion. It was an effort to not breathe in the toxic haze, but he managed it– and this time, when the body reappeared on the tallest roof, he could tell for sure that the demon wasn't an illusion anymore.
“Spoilsports,” she hissed, her expression clearly sharpening from curiosity to annoyance. Her claws slashed downwards, sending arcs of blinding light crashing down.
As Shinazugawa and Giyuu dodged the attacks, blades screeching against the strikes, they landed beside each other, panting. Their fighting styles couldn't be more dissimilar, but for a moment, Giyuu could feel their rhythms syncing.
“Now!” he said, sensing an opening. Shinazugawa seemed to want to snap at him again, but refrained as he lunged upwards in a rush of green-white wind, overwhelming Kuroha's defenses. She struck back with a snarl, but Giyuu was too fast for her, using the cover of Shinazugawa's attacks to swing an arc through her neck.
She pounced back at the last moment, staggering for the first time, but the bell at her neck cracked. The demon eyed Giyuu, irritation fading into something almost wistful.
“You are fun, aren't you?” she hummed, before straightening. “Blood Demon Art: Eclipse Waltz!”
The remainder of all her mirages, shimmering in the night, suddenly convalesced around the demon's trembling form. Light exploded from her, slashing in all directions violently. Giyuu spared no moment to hesitate as he lunged forward, taking the brunt of the attack meant for Shinazugawa.
The force of it knocked him on his back, blood splattering onto the cobblestone. Giyuu felt like all the breath had been knocked out of his chest– but the attack hadn't hit anything vital. As he struggled to catch his breath, Shinazugawa snarled, and Giyuu barely saw any of his movements before the sight of his blade slashing through her heart.
“Wind Breathing, Seventh Form: Gale, Sudden Gusts!”
And just like that, it was all over. The cut cleaved her form apart, scattering her images into silver dust.
Her torso rolled off the roof and landed beside Giyuu, who weakly flinched away. There was a moment of silence before the headless body seemed to laugh softly.
“Ah, I see now…” she mumbled, voice sounding almost broken. It was her life flashing before her eyes, probably, but Giyuu did not care for it, as Tanjiro likely would have done. All he could do was watch as the remains of her body slowly crumbled into the moonlight.
“For you…” a ghostly whisper echoed, startlingly close to him. Before he could react, the demon's remaining hand reached up to his forearm, tracing her claw over the skin. Giyuu stared as the mark shimmered gold, then settled into his skin. “A gift… I did love making you dance.”
And the next moment, she was gone, leaving Giyuu with nothing but the moonlight and the confusion of her last words and actions. He stared at his now empty forearm and shook his head slightly, trying not to think too much of it.
Giyuu could definitely stand to rest for a few days after this. His head felt off-balance somehow, with a faint ringing in his ears, and he felt vaguely overstimulated as the light from dawn began to flood in. Clutching his head, he got up slowly.
“I'm heading back, Tomioka,” Shinazugawa called out. As expected. Giyuu had sensed he'd been waiting to leave him behind. “Given you're not hurt too badly, that is.”
He sounded unenthusiastic about the prospect. Giyuu winced slightly as he got to his feet, hoping his expression would serve its usual purpose of betraying nothing, and turned to face Shinazugawa.
His partner was in the middle of a yawn, in the middle of stretching out his weary limbs. Shinazugawa's eyes flicked lazily to him as he stood up, scanning him up and down and seeming to make up his mind. However, his expression suddenly froze when he caught sight of something just over Giyuu's head.
“Tomioka, what…” he began, expression twisting into an utterly bewildered scowl, “The fuck is that?”
His accusing finger was pointed at something on Giyuu's head. Confused, he reached his hand up to push his hair back– and that's when he felt it. Something soft, warm, triangular, and… twitching?
Giyuu tugged at it, trying to feel for what it could be– and suddenly, impossibly, felt a shock of pain coursing through his own body. He hissed, turning to the side to look at the shattered remains of a nearby reflective window.
The dawn light caught the top of Giyuu's head, illuminating a pair of cat ears on the top of his head– small, black-furred, pressed almost flat against his head. In the distance, a broken bell chimed, almost as if mocking him.
For a long moment, neither of them said anything.
Shinazugawa's brows were drawn tight, jaw twitching with something Giyuu had never seen on his face before. His eyes flitted from the ears on Giyuu's head to his face, then back again, like he couldn't decide which offended him more.
“...You're kidding me,” he muttered finally, pressing his hand to his temple as his jaw ticked.
“No, I'm not,” Giyuu replied, confused. Shinazugawa's shoulders twitched, and his throat bobbed. His mouth opened, like he was going to say something, then promptly snapped shut. Giyuu could see the corner of his lip wobble weirdly.
“You–” he started, before quickly turning his face to the side with a half-strangled noise. If Giyuu didn't know better, he would've thought it was a laugh. “Shit. Never mind.”
Giyuu tilted his head at him, feeling his ears twitch at the motion. Shinazugawa's eyes widened before a snort escaped him, loud and uncontrollable– then silenced almost immediately.
“You're laughing at me,” Giyuu said plainly, almost offended. Shinazugawa's expression twitched violently before he started biting his lip and turned away.
“Why wouldn't I? You look like a fuckin’ idiot,” he said dismissively, waving a hand over his back, beckoning Giyuu to follow. “Well, guess I can't leave you on your own like this. Let's get you to Kochou before I lose my damn mind, catboy.”
“Don't call me that,” said Giyuu, but he followed him without further comment.
The sun was high in the sky by the time they arrived at the Butterfly Mansion, bathing the halls in bright light. Giyuu sat stiffly on the examination bench, the air around him smelling of floral perfume and disinfectant. Maybe the rigid formality was his way of trying to salvage the dignity he had lost on the trip back with Shinazugawa– but with the said man still standing just a few meters away, it was a futile effort.
Giyuu was quite used to being here, for various reasons, but he was less familiar with having the Wind Hashira's gaze bore into him while Kochou flitted around him taking notes. Being stuck with these embarrassing ears was bad enough on its own, but he couldn't help but think it made it worse that Shinazugawa was witness to his humiliation. He'd always cared more about his opinion as compared to others, for unfathomable reasons.
“Please stop moving your ears when I get close, Tomioka-san,” Kochou said, voice brimming with faux sweetness. “I'm still taking notes.”
“I'm not moving them on purpose,” Giyuu replied, pursing his lips as he felt his ears twitch again. Kochou gave him a contemplative stare– behind her, Shinazugawa let out a sound that could be either a cough or a choked laugh.
“They reflexively respond to sound, hmm?” Kochou murmured. “So what if I…”
She raised a hand next to his ear and snapped her fingers, making Giyuu startle and his ears stand up straight.
“An acoustic startle reflex, too! Quite the impressive set of ears you have, Tomioka-san,” she said, seeming to ignore the way Giyuu tried to shrink into himself and wither away. “These observations will be wonderful for my research on Blood Demon Arts.”
Shinazugawa's shoulders had started to shake in earnest as he turned his head towards the window. “This is– ha – this is some serious business, ain't it, Kochou?”
“Quite,” she said, seeming at least partly serious. “I've never seen a transformation like this in a human. Even despite the demon dying, there's still demonic residue clinging to him… and it's not an illusion, rather a physiological change. It's very interesting.”
“So, what, he's half-cat now?”
“Perhaps,” Kochou said serenely. She reached forward to a nearby desk, picking up what looked like a broken tassel from her own haori cords and dangling it over Giyuu. His pupils instinctively dilated, latching onto the movement as it swung from side to side, before pressing his lips together and tearing his gaze away.
“I'm not a house cat, Kochou,” he murmured. Shinazugawa leaned against the wall, clearly having the time of his life.
“Sure you aren't. You looked like you were two seconds away from swatting at it.”
“I am not,” Giyuu insisted, willing his fingers not to twitch as the tassel swayed in his peripheral vision. How annoying.
The tassel swayed again, and again, and again. Giyuu blinked one moment, and the next, the tassel was in his hands, snatched out of Kochou's grasp.
“Impulse inhibition is compromised, I see,” Kochou hummed. Giyuu could see a clear glimmer of enjoyment in her eyes– cruel, he thought, even for her. Behind her, Shinazugawa snorted loudly, seemingly losing the battle against not laughing.
“Please do not contaminate my study with your laughter, Shinazugawa-san,” Kochou said, not even sparing him a glance as she penned down her observations.
“Who's laughing?” Shinazugawa said, wiping a hand across his mouth in a weak attempt to conceal his smirk. “This is tragic. Absolutely tragic.”
“So the good news is,” Kochou said, ignoring the other Hashira, “You're stable. The demonic residue doesn't seem at risk of growing. The bad news is, the changes are physiological and not magical. Which means… I can't reverse them. Not yet.”
At this, Shinazugawa's mood abruptly turned frosty. “You're not serious.”
“I wouldn't joke around about this,” she said, clicking her tongue mildly. “I'll have to monitor him for a while to see what part of Tomioka-san the curse has latched itself to. Until then, my hands are tied.”
“Will I have to stay here, then?” Giyuu asked, a feeling of dread bubbling up in his stomach. The memory of having to stay in a room constantly surrounded by people moving about made him tense up.
“No, since I don't have any free rooms for you. I won't be able to monitor you myself, either, since I have other patients,” Kochou said, pressing a finger to her chin. “In that case, I'll have to assign someone else to monitor you. Someone who already knows about the curse and doesn't have any missions queued up for at least two weeks to come.”
Giyuu and Shinazugawa locked eyes.
“Not him.”
“Not me!”
Kochou laughed lightly. “It seems you are in agreement,” she said, tearing the page out of her notepad. “Just not in the way you should be. Anyways, I'm afraid neither of you has a choice.”
“No fucking way,” Shinazugawa snarled, sounding furious. “You listen here, Kochou, and listen carefully. There is no way in hell I am going to babysit this–”
About an hour later, Giyuu left the Butterfly Mansion with Shinazugawa trailing behind him, grumbling to himself all the while. Crumpled in the younger Hashira's hand was a letter Kochou had written for him, which was to be sent to the Oyakata-sama informing of his accommodation changes and the current situation.
“You don't even have any attendants, from what I've heard,” Shinazugawa grumbled at him. “How am I supposed to stay there?”
Giyuu felt his ears twitch, but paid it no mind. “You are free to invite your own attendants over,” he said. “It's none of my concern.”
“Screw you,” Shinazugawa said, but there wasn't as much venom in it as usual. “Arrogant bastard.”
Giyuu briefly wondered what gave him that impression, then decided it didn’t matter. He knew Shinazugawa didn’t think highly of him in any case, and nothing he could say would change that.
They spent some time walking after that in silence. The dirt path wound through low hills, morning mist clinging to the edges of the trees. Shinazugawa had gone quiet, save for the occasional quiet grumbling that didn’t seem meant for Giyuu’s ears anyway.
Giyuu didn’t mind. He almost always preferred silence.
He was turning Kochou’s instructions over in his mind once more when he heard a group of young voices bickering ahead of them– awfully familiar voices.
Shinazugawa seemed to hear the voices only a few seconds afterwards– courtesy of Giyuu’s enhanced cat hearing, he supposed– then groaning loudly behind him. “You’ve got to be kidding me.”
Not even moments afterwards, rounding the bend came possibly the last person Giyuu wanted to see right now– Kamado Tanjiro, whose ever-present sunny smile only grew wider as he laid eyes on him. Trailing behind him were the two other youngsters who seemed to be attached to him at the hip.
“Giyuu-san!” Tanjiro called out, waving as he jogged slightly to get closer. At a certain distance, though, he faltered, blinking up at the protrusions on his head. “Ah, Giyuu-san… did you change your hair, or something?”
Zenitsu, catching up to him while out of breath, was much less subtle, shrieking unpleasantly loud as he pointed at his head. “Are those– are those cat ears?! What the hell?! He has cat ears!!”
The one with the boar mask caught up not long after, yanking Zenitsu back to get a better look at Giyuu. “No way, Chuitsu’s right. I want those!” He lunged forward with outstretched grabby hands, before Tanjiro quickly caught him by the collar and pulled him back with a Calm down, Inosuke!
Shinazugawa groaned, seemingly resigning himself to the situation. “Keep it down. We don’t need everyone knowing, you damn brats.”
Tanjiro looked at his friends, then back at Giyuu with bewilderment still plastered all over his face. “Giyuu-san, is this…um…normal?”
Giyuu sighed, looking away from the boy and trying not to let his embarrassment show. “No.”
“Is it permanent?” Zenitsu wailed, looking terrified for some unclear reason.
“...Hopefully not,” he replied, though the displeased flattening of his ears at the loud noise didn’t help his case.
Inosuke, having extracted himself from Tanjiro’s half-hearted hold, leaned uncomfortably close to Giyuu in fascination. “Damn, do these move on their own?”
Giyuu swiftly stepped back, cupping a hand over his new ears. “Don’t touch them.”
“Aw, come on! I wanna see if they’re real!”
“Kamado,” Shinazugawa cut in tightly, stepping forward, “I’m not messing around when I say this. Don’t tell anyone– anyone– about what you just saw, understood?”
Tanjiro’s expression turned serious, and he nodded solemnly. “Of course, Shinazugawa-san, Giyuu-san. You can trust me.”
Zenitsu, however, was still shrieking. “But why– how?! What happened?!”
“Shut him up,” Shinazugawa growled.
Inosuke smacked Zenitsu over the head, seeming to be worryingly familiar with the action. “You heard the guy! Shut up! He’s ashamed!”
“I-I’m not ashamed,” Giyuu muttered, frowning.
“I think you are,” Shinazugawa said under his breath, so low only Giyuu could hear.
Tanjiro was still staring, but his expression had morphed into one of awe and concern. “…You know, you actually look kind of cute, Giyuu-san.”
Shinazugawa choked on thin air, glancing back at Giyuu like he was personally responsible for the comment. “What the hell did you just say?”
Tanjiro, realizing too late what he’d said, went pink in the face. “Ah! I didn’t mean cute like, um, cute, just… endearing? In a respectable way, of course—”
Shinazugawa threw his hands up, face screwing up in disgust. “Stop talking!”
Zenitsu, meanwhile, had crumpled to the ground, clutching his head. “First Nezuko-chan, now Tomioka-san?! Why does everyone around me become adorable demons?! What’s next, Inosuke grows bunny ears?!”
“You wish!” Inosuke barked. “I’d get something cool, like horns!” He took a menacing step closer to Giyuu again, eyes glinting. “Come on, let me touch them! I’ll be gentle!”
“You will not,” Giyuu said flatly, stepping neatly out of reach. As he did, something brushed faintly against the back of his leg— soft, light, moving. He frowned, shifting his haori slightly, and caught a glimpse of something dark curling back toward his ankle before vanishing beneath the fabric again. His stomach dropped.
A tail.
He felt it coil tighter as if in response to his realization, the fur brushing against his calf. Giyuu forced his posture to remain still, forcing himself to look forward like nothing had happened. His expression didn’t so much as flicker.
Thankfully, no one seemed to notice his conflict; the three young Slayers focused on Shinazugawa as he snapped at them.
“It’s the Master’s orders, no one should know,” Shinazaugawa said emphatically. It was just Kochou’s orders, really, but Giyuu didn’t bother correcting him in such a situation. “If I hear that any of you breathed a word about this, I’ll–”
Zenitsu nodded so fast his head became a blur. “Didn’t see! Didn’t hear! Don’t even know what a cat is!”
Inosuke crossed his arms, looking betrayed. “You guys are no fun. That’s the coolest thing I’ve ever seen.”
Giyuu turned away from the commotion, voice cool but final. “We should go.”
“Yeah,” Shinazugawa muttered, glaring at the trio. “Remember, I’ll personally end your miserable existence if I hear you say anything.”
“Don’t worry, we really won’t tell anyone,” Tanjiro promised immediately. His eyes locked with Giyuu’s, giving him a softer smile than his usual. “Good luck, Giyuu-san. I hope… it wears off soon.”
Giyuu nodded at him. He turned away, ears twitching once at the sound of Inosuke’s loud complaints, and started back down the path.
Shinazugawa caught up after a few long strides, still radiating frustrated disbelief. “Cute?” he muttered under his breath, scowling hard. “Endearing? The hell is wrong with that kid?”
Giyuu didn’t answer, but the tip of his tail flicked once, betraying the faintest hint of whatever he was feeling– irritation, or perhaps it was amusement.
By the time they reached the Water Estate, the sun was low again— filtered orange light glinting off the surface of the small pond in front of the main house. The air was still, almost reverent. Moss lined the stones along the walkway, and wind chimes murmured softly from under the eaves.
The sight of his estate gate, even if it wasn’t the most homely, would always be a relief to Giyuu’s eyes– especially after a long day. It was now that he would finally allow himself to acknowledge his lack of sleep, the various aches and pains all over his body. Though it might be lonely by others’ standards, he looked forward to curling up in his futon after a cup of freshly-brewed tea.
Shinazugawa seemed to have a different opinion, lip curling in disdain as he stopped at the gate. “Figures your place would be dead quiet.”
“It’s peaceful,” Giyuu replied simply, sliding open the gate.
“Creepy’s another word for it,” Shinazugawa muttered, but he followed anyway, shoes crunching on the gravel of the footpath.
Inside, the estate was just as minimalistic, barely lived in anywhere except the main bedroom and the kitchen. The scent of damp wood and tea leaves lingered in the air. The silence pressed down on them, until Shinazugawa spoke again like he couldn’t stand to prolong it.
“So this is where the great Water Hashira hides from the world. No attendants, no family, no nothing, huh?” He glanced at Giyuu as they passed through the main hall, probably looking for a reaction.
Giyuu didn’t answer. He didn’t think he had anything to say to that, anyway. Instead, he led Shinazugawa towards one of the guest rooms and slid the door open. “You can stay here. There are spare futons in the closet.”
Shinazugawa stepped inside, looking mildly annoyed that he hadn’t risen to the taunt, scanning the empty space. “This room’s as depressing as you are.”
“Then it's a good fit for you,” Giyuu said absently, stepping inside with him out of courtesy.
Shinazugawa blinked, trying to process the words, then scowled. “Did you just— did you just make a joke?”
Giyuu frowned, confused. “No?”
“Then you're just trying to be an ass, huh?” Shinazugawa jabbed a finger toward him in accusation. “Don’t think I didn’t hear that tone. You getting snarky now that you’ve got extra ears?”
At the mention, the ears twitched involuntarily– unmissable. The silence that followed was unbearable.
Shinazugawa sighed through his nose, looking away. “You should probably cover those when you sleep. Before someone walks in and dies of laughter.”
“I wasn’t planning to have visitors,” Giyuu said.
“Yeah, well. You’ve got one now,” Shinazugawa muttered.
He turned to unpack his few belongings, muttering under his breath. Giyuu moved away from him and sat by the open window, hands loosely folded in his lap, gaze unfocused on the drifting koi below. The faint movement of his shadow revealed the slightest flicker of something long swaying behind him– hidden by the haori, but unmistakable to anyone who might have been watching closely.
Shinazugawa didn’t see it, too busy trying to unfold his bedding. Giyuu sighed in relief and closed his eyes as he took in the silence, interrupted only occasionally by the wind chimes.
Until, somewhere outside, a cat yowled, long and low.
Giyuu involuntarily hissed at the sound before catching himself, and Shinazugawa groaned. “If you’re going to do that every time you hear a cat, I’m moving out.”
Giyuu didn’t answer. The silence stretched.
Outside, the wind chime swayed again, soft and deliberate.