Archive of Our Own ^beta

Chapter Text

Human touch was warm. Demons gave off body heat of their own-- they weren’t walking corpses, but living beings in their own right, after all-- but there was something about a human’s hands that felt different. They were softer; gentler; they could reach someone’s core and cradle it as it melted in their palms. 

When his family touched him, playing their roles with all the grace of puppets on a broken string, they were tense and distant despite the contact. The hands that took his own never gripped tightly enough, like they hoped that they might get the chance to slip away, and the fingers that ran through his hair were laden with apprehension rather than affection. On occasion, he embraced them, seeking out the kind of familial comfort that he endlessly craved, but their first response was always to jump. Even those that managed to relax afterward had already ruined the illusion; they always made his skin crawl and never lasted long. It was better to lash out and keep his family in line than try to draw something from them that they were physically incapable of giving; they needed to play their roles acceptably first before he could ask for more, apparently, and they had a long way to go before they felt like a true family. 

But this … 

Two hands bracketed his face, a palm pressed to either cheek, and Rui found himself frozen. They weren't soft and delicate like the hands of other humans; no, they were worn and calloused, scarred from the burden of training and fighting. Hardly a moment ago, they had been clasped tightly around a broken sword, intent on using its stunted blade to slice through his neck; now, they clasped his face and squished his cheeks in, holding his head in place. He didn't know when the boy had cast his sword aside in favor of grabbing his face and, frankly, he didn't especially care. Despite the force behind them, he couldn't help but appreciate how… full the touch was. There was no hesitation, no feather-light brush that would escape him in a moment; no, this was a touch full of intent . Rui could feel all of it. 

And it was warm ; warm in a way that only a human could be. 

The boy’s face was anything but pleasant, though. His expression was twisted up with rage and desperation, features scored by thin cuts from Rui’s threads, and he carried a flush in his cheeks that burned as hot as the flames which had eaten away at his blood demon art. All of the fire that he’d carried in his fight had shifted to his voice, carrying his words to every corner of the forest and every cell in Rui’s head.

“ The bond between Nezuko and I cannot be severed! Not by anyone! I feel sorry that you will never experience something like that!”

There was passion in his eyes as he spoke, adrenaline-fueled desperation leaking from every pore, yet hidden underneath it all was something that made Rui pause. 

Sadness . The boy pitied him, showed sympathy for him, even through such cruel words. He connected with him on a personal level deep enough to feel sorry for him and it caught Rui off guard. 

Even his own family had never regarded him with that kind of heart. They’d never connected with him at all. 

What they had wasn’t a real bond at all.

Before he could sink too deep into thought, the grip on his face tightened and rough fingers curled behind his ears, not giving him any room to back away. It was only then that he realized that the slayer’s face was coming closer, closer, closer-

CRACK!

The boy’s head slammed against his own, the impact resonating through his head and doubling his vision. His skull cracked-- he could feel the bone shatter from the force-- but the hands bracing him prevented his neck from snapping back and following through. Rui gritted his teeth and grunted, shocked and pained, only to stumble back and fall once his head was released. 

He hit the ground with a thud , barely managing to stop himself from cracking the back of his head against the unforgiving forest floor. Propping himself up on his shoulders, he blinked his vision back into focus and felt the ache of his fractured cranium fade as the fragments fused seamlessly back together. Within seconds, the minimal damage that had been done by the slayer’s headbutt had corrected itself, bringing Rui right back to his prime and ready to fight once again.  

But he couldn’t move. 

The slayer stood over him, empty-handed and vulnerable, and it would have been so easy to slice him up into tiny pieces. He wouldn’t be able to jump back in time, and the blade he had foolishly discarded had yet to be reclaimed. Though he was the one still standing on his feet, he had no advantage to speak of, and the more time passed, the more it became apparent to them both. For all intents and purposes, the slayer was dead on his feet.

But Rui couldn’t bring himself to summon new threads; to lash out; to do anything but rest there, clothes dirtied and elbows digging into the ground as the slayer’s words echoed in his head.

I feel sorry that you will never experience something like that. 

You will never experience something like that. 

Never.  

Rui wanted to be angry. It would have been easier to be angry. He knew what to do with anger. But as he stared up at the demon slayer, Rui found that the offense and frustration from earlier insults had all but washed away, replaced by something almost as warm and full as the hands on his face had been. 

Hope . It was a silly thing to feel when faced with a demon slayer, especially one that had somehow briefly gotten the upper hand against him, but there was no mistaking how it swelled within him. 

At first, when he had been so moved by the display of a priceless and true family bond, he had been convinced that the girl was the one he needed. She was already a demon, after all, and it would have been easy to carve out a space for her within his family. He could have forced her to share that bond she had with her brother-- to give up her life in place of his own-- and finally feel the last pieces of his soul fall into place. At least, that had been his original intention. 

But this boy who wasn't afraid to touch him, scold him, connect with him, discipline him…

Maybe he could be the one to finally give him what he so desperately wanted.

The longer that Rui remained immobile on the ground, the more the slayer's expression shifted. Furious desperation flickered and faded into dawning realization and panic as he became aware of his empty hands. His guard spiked and he littered quick glances around their surroundings in search of that discarded, broken blade. Every time his gaze returned to the demon, however, the anxiety lessened, only for a growing confusion to take its place. Eventually, he stopped frantically searching for his sword entirely, instead content to lock eyes with Rui, brow furrowed and bewilderment on full display. 

Both demon and slayer had thoroughly disarmed one another, their fierce fight dwindling to an almost amicable pause, and it was a test of will alone to see who would regain his senses first. 

After a moment, Rui found his voice. It was tight, emotional and unfamiliar, but he forced it out all the same. 

"You," he managed, pushing himself up into a higher sitting position, but making no move to stand. "It's you. You're the one…"

The one who would connect with him beyond a surface level. The one who would show him what a family bond truly felt like. The one who would bring back the pieces of himself that he was missing. 

The one who would save him from the hell he'd fashioned for himself. 

Rui heard his voice begin to tremble. "Tell me your name."

The slayer hesitated, as if debating answering. It was clear that he still couldn't quite figure out what to make of Rui and his sudden capitulation, much less his words. After studying him for a moment longer and deciding that no, he was not being lured into a trap, he replied, "My name is Kamado Tanjiro."

" Tanjiro," Rui echoed, letting the name roll off of his tongue. It was a good name; a kind name; a strong name; one that could easily belong to his new older brother. 

Slowly, he stood up, careful not to make any sudden movements that would startle the slayer and shatter the tentative calm between them. There was guarded tension written into his body that threatened to flare, but he kept it contained until Rui was on his feet. 

“Tanjiro,” Rui repeated, looking at the slayer earnestly. He could feel energy crackling just under his skin, his heart and soul beyond excited at this new opportunity. He was so close to what he wanted that he could feel it. All that was left to do was take it .  

“What if I change the terms of this fight?” he proposed.

“Terms?” Tanjiro’s confusion creased into a frown, that same beautiful protectiveness from earlier taking center stage. What Rui wouldn’t give to be defended in such a way, himself… “What do you mean? There are no terms . I don’t know how many times I have to tell you that you’re not getting Nezuko! She will never be your sister!”

“Not her,” Rui corrected. “I’m not interested in her anymore. I want you instead.” 

Tanjiro blinked. “ Me? ”

“You,” Rui confirmed, pointing directly at the defenseless slayer. “You are everything I need; the perfect big brother. If you agree to be my older brother, then I’ll spare your sister in exchange. Then she can use her own will and feelings to decide whether she wants to stay or go.” Truthfully, he didn’t have much of a preference anymore, so long as he got to keep Tanjiro.

The boy stared at him incredulously, lips parted but unspeaking. There was something building behind his eyes-- the beginning of a new storm-- but in place of fury, he seemed almost… hurt.  

After a moment of silence, Tanjiro found his voice. “...I’m… I’m not perfect . Far from it.”

“I don’t believe you.” How could he, when even that denial was exactly what he needed? The other members of his family had feared him and did everything in their power to assure him that, yes, they were perfect for their roles, only to cross him at every turn. 

But Tanjiro refused to lie and bluff to save his own skin. As far as he was concerned, every word that had passed his lips was true, including the criticisms he’d had the audacity to throw Rui’s way. At the time, it had gotten under the demon’s skin and prodded at a notorious temper, but… 

Well. He hadn’t been wrong . Now that he’d seen a true family bond before his eyes, he could agree with the insulting assessment of his own ‘family.’ 

“Believe it!” Tanjiro shot back. The pain in his eyes increased exponentially, raging with the burden he carried. His jaw clenched, teeth gritted, and his face flushed dark red as he poured out his aching heart. 

“I had younger brothers before that I couldn’t protect, and another younger sister, too! Nezuko is the only family I have left, and it's not because of anything I did!" he exclaimed, pounding over his heart with the palm of his hand. His voice cracked, and the passion behind it moved Rui even further. "I’m not the perfect older brother! I’m nowhere even close!”

Nowhere even close. What a ridiculous assertion to make. Rui didn’t buy it; not for a second. The evidence to the contrary had been presented to him time and time again. No matter what Tanjiro declared to be true, Rui knew better. 

He had to know better. 

“But look at how you fight for your sister! How she fights for you!” he protested, calling back to the display that had touched his very soul and shaken him to the core. The way that they battled so ferociously for one another, as if an inch of their skin scratched was a mortal offense to the other, was beautiful. Rui wished to witness it again and again; to feel for himself the intensity of that familial devotion. 

He gestured openly to their battleground, the phantoms of each attack replaying before his eyes. “That’s love, just like you said! A true family bond! And you…”

Pointing directly at Tanjiro, he felt that treacherous hope swell up in his chest and throb . He wanted this so badly that it hurt -- could cut him down with more force than any blade-- and there was nothing he wouldn’t do to finally grasp it. Finally, what he needed was within his reach, and he refused to let the slayer’s insecurities keep it from him. 

“You can give that to me!” he cried. His hand curled into a fist and he brought it to his chest, holding it right over where his heart pounded and ached . “ I know you can because you’re willing to do what the rest of my family never could!”

That caught Tanjiro off guard, his expression twisting into one of exasperation as he came down from his emotional outburst. “You… What are you talking about!?”

To Rui, the answer was so obvious that it was almost laughable , but of course someone with a proper family bond would never understand the way his soul suffered. 

“You’re not afraid to touch me! Feel for me!” he exclaimed, the desperation for the slayer to understand dripping over every word. Warmth still lingered on his face from where those hands had unflinchingly braced him, malicious intentions ignored in favor of relishing the feeling of such contact, and the fact that Tanjiro had mustered up the ability to express anything deeper than fear towards him made him dizzier than any headbutt could manage. 

He’d gotten the smallest taste of a true older brother and he refused to let go until he was fully satisfied.

“I am stronger than you and could kill you in an instant, but you’re still willing to fight back!” he continued, his passion growing with every word. “You try to force me into my own role as the youngest! If only you would protect me the same way you protect her, then this could be real!”

If only he could experience what it was like to be protected-- to have someone risk their life for him not because they were forced to, but because they loved him enough to try-- then he might recover every piece of himself that he’d lost. 

The silence that followed was deafening; every living creature in the forest seemed to hold its breath. Rui had argued his case with every drop of passion he had left. It had to be enough to reach him.

…Right?

He watched Tanjiro’s expression slowly shift from one of frustration to one of dawning understanding before it finally settled on something sad . Those eyes carried a weight in them that Rui’s false family never dared to bear and it made his stomach twist. 

“...You actually believe that, don’t you?” Tanjiro said after a moment. His voice was small, quiet, directed more towards himself than offering an opening for response. As he spoke, he looked as if he finally realized that he carried the weight of Rui’s soul on his shoulders. “You think that I can give you what Nezuko and I have…”

Suddenly, his eyes widened and he drew in a gasp. “Nezuko!” he cried, his attention snapping from Rui to their surrounding area as if it just dawned on him that his sister wasn’t by his side. Locating her on the ground where she had fallen from her thread bindings, he wasted no time in rushing to her side. 

Rui felt that shift in focus like a dagger to the chest, unable to do anything but watch as Tanjiro chose his sister over him.

Good . This was exactly why he wanted him, wasn’t it? Because he had the capacity to love like that? To form such a strong family bond? Given enough time, Rui could take her place and experience that kind of devotion for himself. He just had to be patient and take the sting. 

So why was there a lump of frustration and longing building up in his throat the longer Tanjiro fussed over his sleeping sister? And why was he allowing it to overwhelm his senses to the point that he hardly recognized the world outside of them? This jealousy… It was getting in his way! 

Maybe obtaining Tanjiro wasn’t enough. Maybe he needed to eliminate the girl so that there was space for him to take her role. Patience was only a virtue when it brought results, after all; otherwise, it was a waste of everyone’s time and a roadblock to getting what he wanted. 

Rui raised his hand, intent on throwing a targeted attack towards the girl before-

“ You did a good job holding out until I got here. Leave the rest to me.”

A soft-spoken voice shattered the illusion of privacy and caught Rui by surprise. His eyes widened, his webs dying before conception as he glanced behind Tanjiro at an approaching man. He looked different from the others that had been traveling through the mountain; he wore a haori with a distinct, unusual pattern, and his aura was different from the weaklings who slaughtered one another. The way that he came towards them with such confidence and no fear put him on a different level than Tanjiro, as well.

A Hashira. How annoying. It was his own fault for getting so absorbed in his goals that he let him get this close, but it would be no issue. Though he hadn’t killed a Hashira before-- hadn’t ever confronted one-- he saw no reason why he couldn’t start then and there. 

He could take care of this pest first and finish his dealings with Tanjiro afterward. 

The Hashira stopped in front of Tanjiro, blocking Rui’s view of his prize, which only served to irritate him further. 

“Did no one ever teach you that it’s rude to butt in on a family’s private conversation?” he asked, his eyes narrowing into a sharpened glare. It had gotten under his skin when Tanjiro meddled in his affairs (before he realized that he was right, of course), and having this stranger do the same only wore his nerves down further. 

His lip curled in a scowl, showing his fangs. “I’ll just kill you quickly so we can get back to the matter at hand.” Once again, he lifted his hands and summoned a swirl of vicious threads, intending to slice through this opponent as quickly and effortlessly as any other. 

The Hashira adjusted his grip on his sword, but made no move to run. 

Fool . 

Rui pulled the threads close, spinning them tightly together and leaving no room for agile escapes. “Blood Demon Art: Cutting Thread Rota-”

“ Rui, don’t !”

 Rui choked on his words, startled by the use of his name. 

Tanjiro’s voice cut through the air, slicing through him as easily as a wicked blade. It was panicked, desperate, and pleading, all but begging him not to unleash his attack. With the Hashira standing in the way, Rui couldn’t see the slayer, but he could perfectly picture his face. 

On the surface, the cry seemed to be self-serving. Distracting Rui would give the Hashira an advantage and potentially lead to his defeat in their minds. A split second could decide a fight, decide who lived and died, and Tanjiro’s plea could shake him just enough to turn the tide. 

But… no. If there was one thing that Rui had realized about this slayer, it was that he was honest and genuine in every way. When he’d criticized his pseudo family, he’d meant every word. When he pitied him, he embraced the feeling. Every stroke of his blade and touch of his hands was full of passion and intent. His words, even the ones that degraded himself, were said with his full chest and backed by every beat of his heart. A boy like this wouldn’t use such an underhanded tactic, would he? 

In Rui’s mind, it left only one option. 

He’s trying to protect me from this Hashira.  

I knew he would be perfect.

Letting his breath out without a word, Rui lowered his hands and allowed the vortex of threads to slow and spread apart. He registered the Hashira moving-- recognized it in how he was given an eyeful of his target, his brother -- and barely had time to process what he was seeing. 

Tanjiro was on his knees, shielding his sister, but his eyes were locked on Rui. Rather than sadness, however, his eyes were burdened with fear. It wasn’t the type of fear that he was accustomed to receiving, though; no, this was a new being of fear. With wide eyes and pinched brows and an open cry left on his lips, he painted a picture that moved Rui’s heart yet again. 

At that moment, Tanjiro did not fear him; rather, he feared for him. 

The terrible sound of a blade slicing through flesh seemed to echo through the forest as useless threads fell to the ground, abandoned in the name of a true family bond. 

...And it felt just as good as he’d imagined. 

Chapter Text

Rui never shied away from his own blood. It was the source of his power and what tied his family together. Sharing it was like forging bonds, imposing his will onto others, and when the effect ran out, it tore at him. On more than one occasion, Lord Muzan had warned him that sharing his blood with others would weaken him-- that he may become stagnant in his rank and never rise-- but he never forbade him from doing it. Even if his words were true and he could have challenged someone of a higher rank for their position if he kept his blood to himself, it had never enticed him the way it should have. At the end of the day, Rui didn’t care about numbers; not as much as he cared about that family bond he so craved. To get what he desired, he would shed blood endlessly and spread it so thin that there was barely any left for himself without a moment of hesitation. 

That said, there was something hauntingly grotesque about watching it gush and drip down onto the forest floor. 

Drip . 

Tanjiro made a strangled sound, caught in his own throat, as if he was unsure whether to cry out or silence himself. He remained staunchly by his sister’s side, shielding her from the violence, but he couldn’t tear his eyes away from the scene he had created. 

Drip.

The Hashira which had lunged at him followed the trail of blood up into the trees and locked eyes with him. His eyes were cold, devoid of any kindness or warmth as he took in the sight of the wounded demon and flicked the blood off of his sword. 

Drip.

Rui balanced himself on a hastily drawn thread using only one foot. From above, he watched as the other limb slowly disintegrated into nothingness and was carried away by the wind. As the last particles of his leg disappeared from sight, he let out a breath he hadn’t realized that he’d been holding.

That had been close . 

There was such a thing as having too much confidence . Rui had seen it time and time again in the form of slayers who would see his apparent youth as a reason to be cocky. Their ends were always quick and easy-- he didn’t have the time or patience to play with arrogant, talentless brats-- and always exactly what they deserved for underestimating him. He knew his own strength, knew where he fit in the hierarchy, and never had any trouble performing exactly how he was meant to. There was no challenger he took on that he did not have the ability to kill if he wanted. 

So how was this Hashira able to cut him? 

He barely saw him move, barely had time to react and, if not for Tanjiro’s desperate cry, may have lost his head to the Hashira’s blade rather than his leg. Had he not taken his new brother’s warning to heart and dropped his offensive stance in favor of an evasive maneuver, he could have found himself decapitated and staring up at a crumbling night sky. 

Rui swallowed. Perhaps Lord Muzan hadn’t been exaggerating just how much weaker sharing his blood would make him; no, perhaps he hadn’t emphasized it enough . 

The events that had nearly led to his death replayed in his head and he found that, beyond the frustration of growing weaker , he was… touched. Truly moved. Facing off against the Hashira had been naive of him in his condition, emotional and unaware of his own change in strength, but Tanjiro… 

Tanjiro had saved him. He’d recognized a difference in strength that Rui himself had been completely blind to and acted to save his life. 

Perfect. He’s absolutely perfect . 

Despite the residual sting in his leg that came from a mercilessly clean cut and the dawning realization that, no, he was not the strongest fighter present, Rui felt… light . 

Happy . 

Hopeful . 

It was almost enough to make him crack a smile. 

Rui gave what remained of his leg a shake, stimulating the cells in his body to generate a new one. He flexed his ankle and toes to test them out before he set them down to stand properly on his thread, no longer performing a balancing act but fully supporting himself, instead. Back at his current peak (which was admittedly much less potent than he’d been lulled into believing by a string of weak opponents) he was ready to fight again, but chose to remain well out of the slayers’ reach instead. 

Tanjiro didn’t want him to fight, so he wouldn’t. He would be a pathetic excuse for a demon if he wasn’t as elusive as he was deadly. 

That motion seemed to be what was needed to break through the tension that had settled on them. The Hashira shifted his grip on his sword and, despite keeping his eyes locked squarely on Rui, spoke clearly to Tanjiro.

"What's going on here?" His lips pursed into a small frown, which was the only indication that he was anything other than neutral to the situation. "Why do you know its name? And why did you call out to it?" 

Rui's eyes narrowed. It?  

"We…" Tanjiro trailed off as he shifted, sitting up a little straighter as he addressed the Hashira. These two knew each other and he trusted this man; Rui could see it in the way that he left his sister slightly more vulnerable in his presence.

He tried to ignore the flash of jealousy that came from the realization. 

"We had a talk," Tanjiro explained. "Before you got here."

"You talked to it?" the Hashira asked in disbelief. For the first time since his arrival, he looked away from Rui and fully took in the image of the siblings on the ground. 

"I did!” Rather than shy away from the incredulity, Tanjiro embraced it; doubled down on it, even if it only served to dig the hole deeper. He refused to deny and reject Rui in the face of authority, just as steadfastly honest and genuine as he was during their fight. 

“Please, listen,” he continued, desperate to be heard out. He looked squarely at the Hashira, as if to trap him with his earnestness.  “I… I understand what our mission is and I won't hesitate to bring my blade down on any demon's neck, but this one…"

This one is different. This one is an exception. This one is important. This one is family.

Rui's mind filled in the blank with a dozen different ways that Tanjiro could silently say he was worth protecting; that he was cared for. Each one made his heart throb just a little more. 

The Hashira opened his mouth to speak, only for a flash of recognition to cross his features and stun him into silence. From that distance, it was difficult to tell exactly which one of the siblings had his attention, but whatever he saw made him pause. Slowly, insult and bewilderment gave way to understanding; the kind of understanding that was heavy and burdened with heartache. 

Pity . Something about the scene before him pulled at his heartstrings in a way that began to erode his guard; something that Rui, himself, was not aware of. Whatever history these two shared, it was taking center stage. 

Once again, jealousy made his gut curl. 

After a moment, the Hashira spoke up. If his eyes betrayed his innermost thoughts, his voice failed to follow suit. There was no sympathy present in his tone as he spoke, but dry insistence alone. 

"You can't save every demon, Tanjiro,” he stated. “This is a Twelve Kizuki. It has devoured dozens of people. It's not like your sister."

Not like your sister. Rui’s lips tugged into a slight frown. That girl-- that Nezuko -- had already been odd enough for fighting alongside a demon slayer, though their bond made it an excusable slight in his eyes. To hear that she had somehow managed to develop a Blood Demon Art that strong without consuming humans took him by surprise. It had easily overpowered his own, even if only briefly, and she hadn’t bolstered her strength with human flesh once? 

Surely, this Hashira must have been mistaken, and Rui was quite tired of hearing his dull voice. 

"It is also standing right here and listening to you talk like it can't hear you ." 

If there was something about demon slayers that got under his skin, it was their blatant disrespect. It manifested in countless different ways, from shamelessly butting in on his business to insulting his prowess as a demon with a pathetic challenge, but one of the most grating (albeit inconsequential) was the use of It. That term stripped a demon of their dignity, likening them to little more than a mindless beast. There was no heart, no soul, no value in their lives when they were regarded as a thing, and it frustrated him. 

His former family had been useless and disappointing, yes, but they’d been more than animals. 

Rui was more than an animal. If anyone present fell into the category of vermin , it was none other than the Hashira, himself. 

Said Hashira glanced back up at him, every trace of sympathy gone from his expression. Instead, those cold eyes were fashioned into a glare as sharp as his blade; a glare that Rui could not only effortlessly meet, but match. Perhaps it wasn’t the wisest idea to actively antagonize a Hashira who had already proven to be more than he could handle in his current state, but Rui had never been very good at avoiding conflict. 

The faint sound of too-light footsteps broke through the haze of mutual disgust, skittering across the forest floor like an insect. After the decades he had spent deep in these woods, Rui had come to know it just as well as he understood himself. Every sound and tremor had a source, a name, an identity, and he had all but memorized each one. This was something foreign; something human; something he had so foolishly overlooked just minutes ago. 

Another Hashira!?  

In a moment of insulting synchronization, both Rui and the Hashira turned towards the source of the sound, and the former could almost taste the adrenaline spike. Without hesitation, Rui raised his hand and summoned wicked threads to his fingertips. He lashed out, the angle of the threads perfect to pass right above Tanjiro’s head as it sliced the oncoming assailant into pieces. It would take only seconds; they had only seconds. 

Unfortunately, the Hashira not only had different plans, but was adept enough to execute them despite Rui’s interference. With one swift movement, invisible to even the trained eye, a blade sliced through his offenses and rendered them useless. In that same motion, he lunged over the huddled siblings, shielding them with his body. There was a blur of color and the sound of metal clashing with metal seemed to echo through the forest as Rui’s threads sagged uselessly to the ground. 

The Hashira had somehow managed to not only protect Tanjiro and his sister, but his advancing colleague, as well. If he wasn’t such a nuisance, Rui may have found the nerve to be impressed.

“Oh my!” a soft voice exclaimed as the attack was deflected. The blur solidified into a human that skidded to a stop a short distance away from the trio. She was a woman of slight build and short stature, made to look impossibly smaller by the haori that flowed loosely around her thin frame. There was a butterfly pinned in her hair and the pattern of her haori resembled delicate wings.

Just like an insect.  

The new intruder turned to face the huddled trio, a gentle smile still gracing her features despite the circumstances. 

“Why would you get in my way, Tomioka? And after you told me that we could never be friends with demons. I have to say, this kind of thing is exactly why no one likes you.” Her voice was gentle on the surface, but harbored something dark just underneath; something just harsh enough to indicate that a dangerous line was being toed. 

Rui’s expression darkened. Friends with demons? That was a delusion he’d never anticipated hearing from a Hashira. It didn’t sound sincere, but more like a trap laid out for those too desperately naive to fall for it. Considering her slight physique, it wouldn’t have surprised him if she had to resort to a number of tricks to claim her victories. 

This was little more than a friendly facade to mask a weak and wicked heart; nothing more, and nothing less. 

His theory was only supported when she raised her blade again, daring to point it directly at Tanjiro and the other Hashira-- this Tomioka . It was thin, lacking the perfectly honed edge that could slice through flesh; instead, it boasted a thick, pointed tip that resembled a stinger. A blade like that wasn’t meant for slashing, but sticking and stabbing. Any death experienced at the hands of this blade was guaranteed to be drawn out and agonizing. Even Rui, himself, had the ability to kill quickly if he so chose, but this thing…

What a cruel weapon to wield. The fact that it was being pointed at Tanjiro was unforgivable. 

“Now then, Tomioka, would you please move?” she requested. Despite the polite phrasing, there was no mistaking that this was much less a request than it was a demand. 

Tension crackled in the air as the two Hashira stared each other down. A weaker being would have held his breath, but Rui was content to watch. If these two would kill one another, it would save him and Tanjiro the headache of having to deal with them. Then they could get back to their own conversation that had been rudely interrupted not once, but twice in the span of a handful of minutes. 

Hashira truly were pests , weren’t they?

"...I don't…” Tomioka broke the silence, his voice odd and somewhat tight. “I don’t think I'm disliked."

Oh.  

What was originally a lit and burning fuse fizzled out, leaving only an awkward smoke in the air that was thick enough to choke on. Human and demon alike stared at him as the tension took on an entirely different flavor. 

"Oh dear.” The other Hashira was the first to recover her tongue and spoke in that same light, quasi-pleasant tone as before. “I do… apologize. You’re only just hearing about this now, then? I’m sorry, I didn’t mean for you to find out this way.” Despite her apparent apology, there doesn’t seem to be a drop of true remorse in her tone. 

This time, it was Tomioka’s turn to choke on the atmosphere he created. 

As much as Rui hated to align himself with a Hashira-- and he truly did hate it-- he couldn’t help but agree with her assessment. There was something about him that was distasteful; something that rubbed him wrong in every imaginable way. The way he moved, the droll of his voice, his terrible manners, his audacity ; it all added up to a nuisance that Rui would prefer to be without. Learning that his colleagues couldn’t stand him, either, wasn’t a surprise. 

What was surprising, however, was the fact that they put up with it. 

In any structured group, there was bound to be discord. The Lower Moons were one example, as they were constantly shifting about and clawing at each other’s throats in a vain attempt to gain Lord Muzan’s favor. They were obsessed with numbers, obsessed with power, and would tear each other to shreds to gain it. They failed to form meaningful bonds with one another and allowed their incompatibility to reign supreme. 

But Lord Muzan did not allot any space for his own displeasure. The moment a Moon crossed him, regardless of their rank, he made quick work of them. Whether that meant demotion or an early demise was dependent on their master’s mood and the severity of the offense, but no disappointment ever went unpunished. 

For years, Rui had applied a similar logic to his own family structure. Whether the members of his pseudo-family actually got along was irrelevant; in front of him, they each had roles to play and jobs to perform. Failure to do so satisfactorily led to consequences. Rui was much more generous than his master-- he allowed his family to beg for their lives and granted mercy when warranted--but his message was clear:

What was unacceptable to him was unacceptable to all, and what was unacceptable would not be handled with kindness. 

So, why did the Hashira allow a man like Tomioka to exist freely within their ranks? If they could not stand him, why not eliminate him? If nothing else, they should be making their displeasure clear; he should have felt their discontent and borne the scars of it rather than been caught by surprise. That was the only way for him to fix how insufferable he was. 

"So, he's like this around his comrades, as well?” Rui asked, frowning down at the two Hashira. “And you tolerate it? Why?"

For the first time since her arrival, the newcomer tipped her head towards the sky and laid eyes on the demon balancing above them. 

"Oh, my!” she exclaimed. “Tomioka, don't tell me that you are protecting this demon as well. Surely you can see what it is." 

"A Twelve Kizuki. I know,” Tomioka confirmed, looking between his two adversaries: a Twelve Kizuki and a fellow Hashira, neither of which were especially pleased with him. What a hole he had dug for himself. He pursed his lips slightly. “I'm not protecting it. It just… dodged."

“ Dodged ?” the other Hashira echoed, looking back at Tomioka in disbelief. When he said nothing to support or refute his statement, she tutted her tongue. “How convenient.” 

Rui wanted to protest, because he did dodge, actually, and it was , in fact, convenient, but he was robbed of the chance when she turned her attention to Tanjiro instead.

“And you, boy!”

Tanjiro, who had been watching the exchange in silent awe, straightened upon being addressed. “Yes, ma’am!”

“What you’re protecting there is actually a demon,” she said, referring to the girl who was still sheltered by Tanjiro’s body. “So please move away before you get hurt.”

The moment those words were out in the open, Tanjiro’s defenses skyrocketed. 

“No! You’re mistaken!” he exclaimed, before hesitating and backpedaling slightly. He was too genuine not to. “Well, you’re not mistaken, but she’s my little sister. She’s my sister, and that’s why…”

That’s why he would go to the ends of the earth to protect her. That’s why he would take on a member of the Twelve Kizuki to keep her safe despite knowing that he stood no chance at winning. That’s why he was everything Rui could have asked for in an older brother. 

“Oh, my. Is that really true?” the Hashira asked, faux sympathy on full display. “You poor thing. In that case, so she won’t suffer, I’ll use a gentle toxin in order to kill her.” She tipped her head in a gesture that was doubtlessly meant to be placating, but in reality was cold and unshakeable. There was a threat behind her every word that one would have to be deaf not to hear. “But if you wouldn’t mind moving out of the way, I would like to eliminate her quickly so that Tomioka and I can focus on the bigger threat.”

Tanjiro’s eyes widened. “Huh? No, wait-”

Rui stared down at the unfolding scene with a frown, his fingers flexing and unsure. 

But Tomioka could move faster than the eye could see. He’d proven on more than one occasion that his relentless speed surpassed Rui’s offenses and rendered them useless. As much as he hated to admit it, the Hashira could probably protect his comrade and return to Tanjiro’s side in the time it took the demon to blink. This unfortunate admission led to one final question:

Was Rui willing to be the one who died for the sake of his family?

Over the years, he had lost track of the number of times he’d stepped up and protected his former family from whatever troubled them. Time and time again, he’d been forced to shed his role as the youngest in favor of defending their lives. It was the burden he always bore as the strongest of his clan, whether he wanted to carry it or not. For all they tried, his family had never been strong enough to return the favor. Not fully. Not in any way that mattered. 

Being the one protected was new. It was such a simple action, executed in the form of words cried out on impulse, but it had moved him far more deeply than Tanjiro could have anticipated. It had prompted Rui to fall back, to trust someone else’s judgment above his own, and put his life into the slayer’s hands. In doing so, he’d lost his leg and received one hell of a wake up call, but went on to take another breath. Tanjiro may not have risked everything for him in a traditional sense-- not in the way he did for his sister-- but he had still put his neck on the line for Rui’s own. 

Like a true big brother. Like the perfect big brother that Rui knew in his core that he was. 

It had only been a small taste of the family bond that he’d been craving, but even as that blade had sliced through his flesh, he’d felt almost airily giddy. In giving him that opening to escape his fate, however, Tanjiro had made himself vulnerable to the whims of a wicked Hashira who knew nothing of the importance of family bonds. 

Despite having attempted to eliminate the demon girl in order to carve out a space for himself in Tanjiro’s heart just moments before, Rui recognized that it was his turn to play protector once again. This time, however, he felt far less bitter about the shift in dynamic. Something about the reciprocity made it easier to swallow. 

Even if it led to his death this time (which it surely would, as it would shatter the tentative peace established between demon, slayer, and Hashira), it would be worth it. 

Maybe losing his head for his brother’s sake would feel just as sweet… 

Before the threads on his fingers could manifest into more than a fleeting thought in his mind, however, Tomioka broke through the tension with his words. 

“Can you move?” He didn’t look away from the other Hashira as he spoke, though his words were clearly directed towards Tanjiro alone. There was a tense weight in his tone-- something that grit its teeth and bit out “ Are you sure you know what you’re doing? Because I’m trusting you.” without ever parting its lips-- and they all felt its effects. “Even if it’s difficult, you need to go. Take your sister and run.”

“Tomioka…” Tanjiro’s voice was breathless, awestruck by the opportunity provided to him. “Thank you. I appreciate this!”

Just like that, any sacrificial consideration Rui had made vanished. Once again, Tomioka had proven to be faster than him, acting decisively while he teetered on the edge of his ideals. It was then that Rui realized why he was allowed within the Hashira’s ranks. Though he was a nuisance, barely tolerable by even his own comrades, he was a silent dominator. He directed the flow of the fight, executing his will with the effortless relentlessness of a coursing river. 

He had carved out this route of escape for them through sheer will alone, and as much as Rui hated to admit it, they would be foolish not to take it. 

After scooping his sister up, Tanjiro looked up at him and met his gaze. Those dark red eyes that had once looked at him with fury and desperation now shone with urgency. Though he couldn’t speak, couldn’t worsen the situation with yet another protective outcry, the demon heard the message behind them as clearly as if it had been shouted directly into his ear. 

Run!

While Tanjiro and his sister fled in one direction, Rui took the other, increasing the distance between them with every step. Escaping side-by-side would have been suicide. If Tomioka somehow lost his hold over the other Hashira-- if he was executed for his insubordination right then and there-- she would have to choose a demon to chase. As the so-called “ bigger threat” , Rui had high hopes that it would be him. 

He remained up high while he fled, darting from tree to tree until the threat of the rising sun sank into his bones and sent him back to the forest floor. No matter the age or strength of a demon, the innate fear of the sun was something that connected them all; something that no demon, from fledglings to the ancient Upper Moons, could ever shed. 

As Rui watched the sky turn pink from the safe shadows of his home, his mind raced. In his nose, he clung to the scent of Tanjiro and committed it to memory. Come nighttime, the forest would be clear of pesky slayers, but their scents would linger as a grotesque reminder of how his home was violated. But if he could hold on to just one … 

He curled up tighter and rested his chin on his knees. It didn’t matter that the family he’d stitched together had been slain. They’d been useless, unfit for their roles, and reeked of misery. So long as he could pick up Tanjiro’s scent that night, there was a family waiting for him just beyond the trees. 

All he had to do was find them , and once he did, they would never leave his sight again.