Chapter Text
At first, Nezuko thinks she’s hallucinating. Imagining things. That, after all this time, she has finally lost it.
He’s only ten sword lengths away.
Red hair, folding over thin shoulders; a fiery cascade of somewhat tempered chaos. Shorter than Nezuko—by a few inches, now, not just by a little bit—and a familiar build.
It can’t be her brother, even as her gut insists that it is.
Abruptly, the demon turns, their hair swishing around their neck, blood-red eyes locking onto Nezuko.
All of the air is sucked out of her lungs. She’s hallucinating—has to be—but the singular Hanafuda earring, swaying with the sudden movement, brushing against a thin child's neck, says otherwise.
The demon tilts its head, his head, Tanjiro’s head, and the chorus of Demon Slayers surrounding Nezuko shout, “Demon! Demon!” as they recklessly draw their blades and charge forward.
Before she can say something (What would she even say? Would she call his name? Tell the other slayers to stop? Cry?) the demon leaps.
Not toward them, thankfully, but away. Even so, Nezuko does not know whether to be relieved or frustrated as he swiftly vanishes deeper into the dense woods that surround them, straying off the beaten trail, swallowed by the underbrush in seconds.
Without consulting Nezuko, the slayers with her—five people that Genya would unkindly call “No names” without remorse until herself and Kanao pinned him in place with a disapproving look—dart forward in an attempt to follow the demon. Part of her wants to call them back for reasons other than stupidity.
…Which is, Nezuko knows, a dangerous train of thought. Even if it is Tanjiro, that demon is no longer her brother. He wouldn’t remember her, all traces of his human past washed away, all traces of humanity gone with that first taste of human flesh he has undoubtedly consumed. And yet, there is a not-insignificant part of her that wants to crush him in her arms in a hug that would be too violent for their past selves to even comprehend.
But for now, she has some Demon Slayers to chase down and berate for being reckless.
Unfortunately—or perhaps fortunately, Nezuko isn’t quite sure, regret and relief grating against each other with every step—they don’t catch Tanjiro. Catch the demon. Because even though all signs point to that being… that being him, Nezuko still isn’t sure.
(She’s deluding herself. Her brother has been so far out of reach for so long—such a distant goal—that Nezuko doesn’t know how to handle the idea of finally catching up to him.)
The group had fallen into line behind her after their harsh (by Nezuko’s standards) reprimand, swords up and on guard, while Nezuko’s hand remains on the pommel of her katana, ready to draw it at a moment’s notice. She’s hesitant to have the group spread out and search for the demon, especially since she is pretty sure, with the addition of the second demon (of her brother?), that there are at least two demons lurking in this stretch of woods, somewhere on the mountain. The reason she was dispatched here in the first place was to respond to rumors of children going missing after venturing into the forests from a nearby settlement at the base of the mountain—reminiscent, in some ways, of Nezuko’s childhood home.
Examining the village had led to nothing—no clues or signs of demons—which left the forest to examine.
Why Nezuko feels positive that the missing children are not the work of the second demon, she is unsure. Maybe foolishness, maybe a willful blindness. But also partly because the demon had ran upon seeing them: fleeing when he could have pounced and preyed upon their blatant display of reckless foolishness.
Or maybe it is just Nezuko’s gut.
She halts in her tracks. The slayer behind her bumps into her, having not noticed her stopping, and like little ducklings the rest of them slow, too, crowding behind her back.
“What happened?” One of them grouches, still bristling over having to report to someone half his age, “Why’d you stop?”
With a steady hand, Nezuko points upward.
A sharp inhale to her left. “Are those…?”
“Bodies,” Nezuko confirms, “At least fifty of them.”
Wrapped in circular cocoons, hanging from the branches of the tall trees surrounding them, were at least fifty dead or dying people.
Snapping into action, Nezuko points to three of the five Slayers, “Check the cocoons. See if anyone is alive. Watch your back, stick together.” To kill so many people without being noticed would mean that this was likely a stronger demon than the average swordsman was prepared to deal with. With the lives of five comrades in her hands, and with so many dead bodies around them, Nezuko pushes any last thoughts of Tanjiro from her mind. She cannot afford to lose focus.
Most of the cocoons had already liquified their captives. There were, out of fifty, four that were still alive, in varying stages of decay. One, Nezuko learned—the most coherent among them—was a merchant, who claims that his companions went crazy while traveling through the forest, suddenly charging at the others and trying to kill them. Even stranger: his companions had been fiercely apologetic while doing so, claiming they lost control of their bodies. He had ran, in an attempt to escape the chaos, and then been swallowed up by the cocoon.
His estimate of when the event occurred was foggy at best, but based on the information, Nezuko would guess that he had been inside the cocoon for less than a day. The merchant was able to identify two of the other three bodies as members of his group, while the last was a child who Nezuko knew—through interviews in the village—had disappeared only hours before their arrival.
Hesitant to part with anyone, lest they be attacked again, Nezuko decided against splitting up despite the urges from her companions to do so. They wanted to part ways: half of the group escorting the victims back to the village, while the other three continued on. However, with forty cocoons still swaying above them, Nezuko was unmoved.
“We still don’t know what caused the other merchants to start attacking,” Nezuko states firmly, trying to muster a shadow of Kocho or Rengoku’s stern finality, “It’s reckless to split up. We are all going back to the village.”
Her words must have been convincing enough—or perhaps it was the still horror-struck looks on the survivors’ faces—as no one else complains. Four survivors and five slayers… Nezuko keeps her hands free at the front of the group, ready to guard against any exterior threats.
So really, it is her own fault for being caught off guard.
She was only looking for external threats, after all.
There’s a shout behind her—too garbled to be words, but a warning nonetheless—that has Nezuko twisting around as she pushes away from the group. Quick, but not fast enough, as the tip of a Slayer’s sword digs into her shoulder, cutting a chunk away, before she could get out of range.
Blood immediately starts welling up from the injury, sticky and warm as it slowly stains her uniform and haori. Thankfully, the cut isn’t too deep: just wide. Still painful, but no matter.
“I'm sorry!” The Slayer yells, oddly enough, Nezuko’s blood dripping off of the end of his katana. It is the slayer who has been pushing against her the most, throughout everything. She knew he was upset, but not this upset—
“I can’t control—” he cuts himself off with a strangled yelp of pain as his sword darts forward again, somehow pulling his arm right out of its socket, dropping the first merchant in the process, who shuffles backward in wide-eyed horror.
“It’s happening again!” The merchant cries, “They’re— They’ve gone crazy!”
Three more thumps. People hitting the ground as their temporary supports drop them. More awkwardly held limbs and frantic protests that they aren’t the ones controlling their bodies.
Nezuko dodges their swords with ease, despite her injury, and tries to figure out what is going on.
“We can’t—!” One Slayer sobs, their arm bent at an awful angle,
“Help,
please.”
A frantic yelp has Nezuko glancing at the merchants, two of whom are stiffly standing up, arms reaching for the sky, limbs otherwise locked.
“It’s happening again. It’s happening again!” They cry in tandem, before one voice abruptly cuts out, head twisting backward, snapping the merchant’s neck even as his body stays upright.
Dodging back from another sloppy attack, the child—who is crying, sobbing out inaudible words—lunges forward in a sloppy attempt to attack Nezuko. The moonlight glints through the leaves of the trees, bouncing off of the thin lines connected to the child’s limbs, moving her like a puppet.
Nezuko draws her sword. The child sobs harder. She swings—the child, and everyone else, flinches—cutting through the threads above the child’s head. She drops, limbs no longer being controlled, and Nezuko’s face lights up in realization.
With a few rapid swings of her sword, and narrow dodges, she slices through the remaining threads, merchants and Slayers both collapsing now that they were no longer being controlled. Even so, the damage has been done. The puppeteer obviously has no regard for human limitations, pulling limbs out of sockets, twisting heads in truly awful ways.
Two slayers and a merchant, whose head is on backwards, do not stand back up.
This time, Nezuko stays at the back of the group, child cradled against her front, and watches for spiders until they reach the village, where sobbing parents reach for their daughter, healers reach for the injured, and Nezuko reaches for her sword, a sharp command halting the remaining swordsmen in place as she turns toward the mountain.
Alone.
The puppeteer falls first. She comes to Nezuko, rather than making Nezuko find her, and says, Please. Please just kill me. I failed. He’ll kill me if I fail, just please make it fast.
There are tears in her eyes, even as she refuses to sob, darkness overtaking the last of bone-white hair as it soaks across her head like ink, shrinking shorter and shorter: a woman turned child. Nezuko obliges, makes the path of her blade as smooth as possible, attempts to emulate the quiet grace of Tomioka. Perhaps she fails, perhaps she succeeds, Nezuko will never know, aside from the fact that the child puppeteer dies with a warning on her lips: a final kindness.
There are four others on this mountain.
The pain of her injured shoulder forces her to stand upright, torso squared and ready to face the future. Just like she has no choice in regards to her next actions, Nezuko has no choice between slumping and standing upright. All she can do is keep on moving, keep standing tall, in spite of her failure to keep everyone safe.
(This is why she cannot be a Hashira.)
If Tanjiro were here—the real Tanjiro—he would have been able to sniff out the other demons on the mountain. Or Inosuke could have sensed them, with the same ability he used to figure out where Tomioka and Kocho had gone. Kanao wouldn’t have been caught unaware, and Genya could have healed himself, rather than be stuck with a shoulder that was oozing blood in steady streams, the movement of her arms and the width of the injury keeping it from clotting.
She’s not any of them, not even close, and Nezuko realizes with no small amount of dread that she has never been a drawn-out fighter. In training, sure, Rengoku and Shinazugawa both had stressed the importance of endurance, but even her fight against Upper Six had been brief, consisting of one short burst of speed and a dramatic final move; stealing, perhaps, the more rightfully deserved glory from Tomioka, who actually survived fighting Gyutaro. A far more impressive feat.
But they were not here. Even her crow is gone: sent off to mobilize the Kakushi for medical aid, which meant that the demons had to be killed beforehand in order to make the scene safe.
Which left Nezuko—just Nezuko—alone, and for the first time in a while, she is completely, utterly on her own.
Alone.
And yet, Rengoku’s voice echoes in her ear. Directions, lessons, bits of wisdom that he shared with a joy Nezuko never quite understood.
But maybe she understands him a bit more now.
Look for signs of something odd occurring. Gouges in wood, something not-quite-right. Many demons have hideouts, or one specific haunt.
A house, upside down in the air, found while making a wide circle of the mountain, found by noticing the little spiders with strange human heads and searching for where their populations were the densest. Hyper-aware of her own skin, avoiding getting bit was easy, being fast enough to kill the spider with the head of a human was even easier. But there were still more to find.
Another circle, narrower this time, and by the time her sword slides through the sturdy neck of freakishly tall demon with long, white hair—the inverse of the last, with the face of a spider and body of a human—Nezuko realizes that her method of searching is not efficient. It will tire her out before she is done.
Close your eyes. Breathe. Feel. Nezuko, can you feel it? Can you feel the world around you?
She never quite grasped what Rengoku was trying to teach her. But Inosuke… he had felt the world, hadn’t he? Spread out his hands, palms out, and breathed.
She’d asked him, afterward, how he did it. Been in awe of how easily he’d slipped from sensing just beyond his skin to sensing the world.
“Uhh…” he had muttered, before gathering himself up in a show of bolstered bravado, “Being raised on a mountain made me extra sensitive to touch! I use that to feel the vibrations in the air!”
A feat far beyond Nezuko’s own abilities, sure, but useful information nonetheless. The vibrations—the tiny traces of what was occurring farther away…
She uses the tip of her sword to draw an oval in the dirt—the mountain—marking the places where the three other demons had been, and any other signs of demon activity she can remember.
The cocoons had been focused on the eastern side of the mountain—semi-near the village—the demon in charge of those still unfound. The eastern side was where the trees were thinner, easier for people to pass through, a prime spot for catching travelers unaware. The upside-down house, however, had been to the west: further from the sun as it rises. More time to hide. Denser, thicker trees. A stationary hideout.
Nezuko was now in the northern portion of the mountain, having just killed the large spider-headed-demon. The puppeteer had been in the southeast, though she had been walking toward the village, so perhaps her main haunt was in the southern portion of the mountain.
Four points, all the cardinal directions.
Five demons, two still missing.
Although purely an assumption, with the cohesive theme of the spiders between the demons Nezuko has killed, she would be more surprised to find there was no organization of location.
She turns to the south. Up the mountain.
There are two demons waiting for her.
Both appear young, though appearance matters little when it comes to the age of demons. An older girl, though still a child, and a younger boy. Siblings, perhaps. The girl looks at Nezuko with a not-insignificant expression of fear, while the boy glares at her in disgust.
In one of his eyes is the kanji for Lower. The other eye is covered by thick white bangs, hiding away his rank.
“How dare you.” The boy hisses, “How dare you destroy my family!?”
Behind him, the color starts to seep into the girl’s hair as her terror grows more pronounced, inky black staining the bone-white strands, similar to the puppeteer.
How odd.
“I’m sorry,” Nezuko apologizes sincerely, “For taking away your family. But you’re hurting people. I can’t stand by and let that happen.”
Clasping his hands together for a singular second, he draws them apart to reveal thin, blood-red strands, connected between a hundred different points on his palm in an interweaving maze. “You are not the mother,” He retorts coldly, “You do not get to scold me. That is her job!”
With the final word, he pushes his hands outward, palms facing Nezuko, in a pose eerily reminiscent of her fight with Lower Moon One that seems like it was so, so long ago. Only this time, there was no Genya to shoot out his palms. No Kanao to chop off his hands. Just Nezuko, and her sword, and the bright flame of Rengoku’s sword-guard as it swings through the air in the fourth form, Blooming Flame Undulation: a circular arc of defense.
A thread blows past her guard, narrowly missing her head, which jolts to the side instinctively. The threat scrapes the skin of her cheek, skinning it, and the wet tang of her own blood clogs her nose. Already she has run around the mountain twice killing demons, doing so with an arm that is growing heavier and more difficult to keep from trembling as blood continues to stain Tanjiro’s haori. Now, with blood dripping down her face, Nezuko knows that she cannot let this fight draw out. She cannot wait to create an intricate plan; to figure out what, exactly, those threads are made of, or analyze fighting patterns. That will wear her out. The only choice—the only choice she’s left herself, after a series of unpreventable mistakes—is to go fast, to go hard, and to not provide an opportunity for retaliation.
Even if that means getting cut up in the process.
Nezuko is quick, yes, but she isn’t quick enough to stop all of the threads from cutting her, seeing as her defense is not nearly as sturdy as Tomioka. Her speed exists in crossing distances quickly, in power that surges from her heart, to her legs, and into the ground: not from how fast she can swing her sword. Not like Kocho. Like Mitsuri.
So she sinks into herself, imagines compacting down the flames inside of her into one narrow core, and when the next wave of bloody threads comes flying, she defends only that core: the most necessary parts of herself.
Blood drips down her arms, her legs, deep scratches that carve away skin, but her torso remains untouched, her vision still clear, her heart and lungs still pumping at full power.
Breathe in.
Another wave of threads, an angry shout that Nezuko doesn’t hear, the flames narrow.
Thinner, smaller, like one of Genya’s bullets, darting forward in a straightforward and precise path; the length of her blade is lost to both Nezuko and the demon, more strings appear, right in Nezuko’s face, one braid falls to the floor, but her disguised blade—hidden through means Nezuko does not understand, but believes has something to do with the sun inside of her chest, forged through a condensed fire—darts in close.
A thread snakes around her lower leg, ready to snap shut. Fear clamps her heart, stalls her movements. She does not want to lose her leg. Nezuko aborts her frantic dart forward, skidding backward on her free foot while the other snaps upward, kicking out, slicing through the thread with the blade on her shin before it can entirely snap shut. The blade snaps from the force, but still cuts the thread.
Then Nezuko makes her worst mistake yet: she falters. Air escapes through her teeth in a violent, pained hiss as attempting to put pressure on the limb has her nearly falling over. The thread had dug nearly an inch into the surface of Nezuko’s skin on all sides except the front, where the blade resided.
One braid, one usable leg, bleeding from a scattering of deep cuts… Nezuko bites back her pain. She cannot afford to panic.
The sister unfreezes, clapping her hands frantically, her voice high pitched and squeaky, “Good job, Rui! You did it!”
Slowly, Rui turns around to look at the older sister. Nezuko can see the moment he takes in her short, inky black hair, her black eyes, devoid of the cohesive spider-white color that has been consistent among all the demons on the mountain.
Although Nezuko cannot see his face, she can feel his fury.
Voice tight, he asks the demon, “Are you incompetent?”
She blanches, the clapping coming to a sharp, sudden halt. Instantly, white floods through her hair, lengthening it, and her eyes are halfway through changing back when the Lower Moon—Rui—grabs her by the throat, sharp nails digging into pure white flesh.
“What an awful big sister,” he remarks dully, even as his fury is betrayed by his tight grip on her throat, “Making the little brother protect her.”
The demon’s legs don’t even strain toward the ground, her body entirely limp.
It is horrifying: this show of obedience.
Cautiously, Nezuko speaks up, “But little siblings can protect older siblings.”
Rui’s head snaps around, just enough that Nezuko can see one eye, the one that says Lower Moon, full of judgment and disgust.
And, damningly, a little bit of confusion. Nezuko latches onto the emotion, continuing on, “I have younger siblings and an older brother. And I always wanted to take care of him when he was sick, to lessen his burdens. Just because he’s older than me doesn’t mean I’m not protective over him. I would do… I would do anything to save him.”
Including, Nezuko doesn’t say, Killing him.
Blood coats the space between her fingers, making her grip on the handle of her katana slippery. Even so, it is tight and intense: unfaltering.
But Rui falters.
“Little siblings aren’t supposed to protect older siblings,” he says, although his words sound more like a question than the statement they were supposed to be.
Shrugging, Nezuko watches as the blood flows in rivers from five finger-sized holes in the demon girl’s neck, running down Rui’s arm, down the front of her body. “Siblings are siblings because they protect each other. Doesn’t matter how strong they are.”
For a moment, Nezuko doesn’t know what Rui will do next. He cocks his head appraisingly, looking Nezuko over for a moment longer, before crushing his hand into a fist, bloodily separating the demon girl’s head from her body. Even though the blow is not lethal, she does not attempt to grab her head: just allows herself to lay there in two pieces.
“You can be my new sister,” Rui decides, oblivious to Nezuko’s surprise and bafflement, “My twin. My only family. Everyone else is gone—they were useless, anyway—so we can protect each other. Who is older won’t matter then.”
Carefully, Nezuko lowers her sword. Just a little. Just enough to be convincing. Just enough to…
“Alright,” Nezuko agrees, “You can be my brother.”