51-55

Chapter 51: "Breathing Techniques" and Natagumo Mountain

Uchiha Hikari spent a bit more time tracking down and sealing the third chubby demon in the house. 

Witnessing this firsthand, Agatsuma Zenitsu finally believed what Tanjiro had said about their "senpai." The way he looked at her shifted, carrying a subtle hint of awe. 

Next, Uchiha Hikari returned to the car to report the test results to Bulma. 

Meanwhile, Tanjiro and Zenitsu began rescuing the hostages who had been captured, tending to the wounded by bandaging their injuries and escorting them back to nearby villages. 

Once everything settled down… 

Hashibira Inosuke, wearing his boar mask and not the sharpest tool in the shed, showed up late. Mistaking Bulma’s car for a demon, he sparked a small skirmish with Hikari’s group. 

Hikari effortlessly subdued Inosuke, giving the trio a taste of Naruto-style taijutsu shock. Then, she proposed observing their respective "Breathing Techniques." 

… 

In the Demon Slayer world, "Breathing Techniques" originated from Tsugikuni Yoriichi’s "Sun Breathing." 

These were techniques honed over centuries by demon hunters to fight demons with human bodies. By using specialized breathing methods, they could drastically enhance their heart and lung functions, boosting physical abilities to rival those of demons. 

After Yoriichi’s death, "Sun Breathing" was lost. What remained were five derivative styles—Water, Flame, Wind, Thunder, and Stone—along with their offshoot branches. 

Tanjiro practiced Water Breathing, Zenitsu used Thunder Breathing, and Inosuke had created his own Beast Breathing, which was closest to the Wind style among the five core types. 

"Water Breathing, First Form: Water Surface Slash!" 

"Second Form: Water Wheel!" 

"…Tenth Form: Life Flowing!" 

In a clearing near the demon’s house… 

Bulma and a shadow clone were spreading out a tablecloth, prepping for a picnic. 

Hikari’s real body stood under a large tree, arms crossed, her Sharingan’s three tomoe clearly visible in her eyes. She watched Tanjiro perform all ten forms of Water Breathing in sequence. 

When he finished the final move, "Life Flowing," Tanjiro paused to catch his breath and turned back to say, “Hikari-san, that’s everything I’ve learned in two years. I’m still not great at it. If it were Urokodaki-sensei, he’d definitely do it better.” 

“Hm…” 

Hikari nodded. 

After a brief moment of recollection, she drew a short blade from behind her, stepped forward, and swung it decisively. 

“First Form: Water Surface Slash!” 

“Second Form…” 

“Tenth Form…” 

In just a few minutes… 

Hikari perfectly replicated all ten forms of Water Breathing. It wasn’t just similar—it was identical. Her slender, agile frame gave the forms an ethereal, flowing quality, like a water fairy dancing on waves. 

As she landed from midair, delicate water threads scattered around her, soaking the ground as if a light rain had fallen. 

“?!” 

Tanjiro and the others’ jaws dropped. 

“Hikari-san, was that really your first time seeing Water Breathing? You learned it just by watching once?” 

“I trained under Kuwajima-sensei for years! How can someone be this gifted? Even the Hashira of the Demon Slayer Corps couldn’t pull that off!”  

“…Tch, genius? It’s just a shortcut.” 

Unlike Tanjiro’s shock, Hikari seemed a bit dissatisfied. 

“The breathing rhythm felt slightly off. The fusion of Water Breathing and the sword forms isn’t perfect yet… Is it because I copied Tanjiro?” 

Fair point. 

At this stage, Tanjiro had only recently passed the Demon Slayer entrance exam. Though he was progressing quickly, he was still far from veterans like Urokodaki or Tomioka Giyu. For instance, he didn’t even know about "Total Concentration: Constant" yet. Hikari would have to experiment on her own or wait a few days to meet the current Water Hashira, Tomioka Giyu, and copy him instead. 

After a brief moment of thought, Hikari lifted her chin. “Your turn, Zenitsu. Show me your Thunder Breathing.” 

“…” 

Next, Hikari copied Zenitsu’s Thunder Breathing and Inosuke’s Beast Breathing. 

However, for Thunder Breathing, she only learned “First Form: Thunderclap and Flash.” 

Because that’s the only move Zenitsu knew. 

Hikari had also wanted to see Tanjiro’s “Hinokami Kagura”—a youthful version of Sun Breathing—but Tanjiro hadn’t yet awakened the ancestral memories etched in his DNA. His attempt was visibly shaky, so they dropped it. 

“Fine.” 

“I’ll copy the other Breathing Techniques when I meet the Hashira of the Demon Slayer Corps.” 

“I wonder if the ‘Yatayume’ ability can help Tanjiro recall the full Hinokami Kagura… Nah, I’m not skilled enough yet. I’ll practice on those demons first and perfect it before trying.” 

As thanks for letting her copy their Breathing Techniques, Hikari broke a Senzu Bean in half and gave one piece each to Zenitsu and Inosuke. 

“These are incredibly rare. They can heal your injuries and restore your stamina in seconds, even if you’re missing an arm or leg. Ask Tanjiro about their effects. Save them for a critical moment.” 

“…Thank you.” 

After Tanjiro vividly described the miraculous effects of the Senzu Bean, both Zenitsu and Inosuke carefully stored their halves. 

On the other side, Bulma waved. “Come on, everyone, time to eat!” 

“Woohoo!” 

… 

After resting for a day, Hikari’s group set off again. 

They passed through some scenic spots along the way, and Bulma stopped to snap a few photos. 

The camera, even rarer than the car, amazed Tanjiro, Zenitsu, and Nezuko. Bulma generously lent it out, teaching them how to use it. Zenitsu, the quickest to learn, dragged Tanjiro and Nezuko into a selfie session. 

Inosuke, however, refused to join, claiming the machine would “suck out his soul.” 

…Talk about old-school. 

They traveled like they were on a field trip until the evening of the next day, when they arrived at their next mission: Natagumo Mountain, home to Rui, the Lower Rank Five of the Twelve Kizuki. 

The towering mountains loomed before them, covered in lush greenery from the base up. Looking from the foot of the mountain, the path was visible for only a few dozen meters before dense forest shadows swallowed it, giving off an eerie, mysterious vibe. 

Driving was no longer an option here. 

Plus, it was nighttime—when demons were most active. Bulma stored the RV in a Capsule, handed Hikari the protective suit and laser sword, and put on her mini-bracelet, ready to transform at a moment’s notice. 

Chapter 52: The Shooting Star Falls on Spider Mountain! 

Rustle, rustle— 

The sound of footsteps echoed along the mountain path. 

Maybe because they had strength in numbers, even Agatsuma Zenitsu, who was usually the most terrified when facing demons, didn’t voice any complaints about being scared. He just subtly shuffled closer to Kamado Tanjiro and Uchiha Hikari’s positions. 

As they moved forward… 

Bulma muttered under her breath, “Hikari, don’t you think the vibe on this mountain is super creepy? There’s no way actual demons are lurking here, right?” 

“Yep, there are. And not just any demons—real Twelve Kizuki, too.” 

Uchiha Hikari replied casually, already plotting her hunting strategy in her mind. 

The demon holed up on Spider Mountain, Lower Rank Five Rui, was a peculiar one. 

Due to his past life, he had an almost obsessive fixation on family bonds. He liked to “adopt” stray demons who fled to him, playing a twisted game of house. His makeshift “family” could number as many as a dozen at its peak, or at least five or six at its lowest. 

For the Demon Slayer Corps, this was a nightmare of an enemy. So far, over a dozen Demon Slayers had gone missing here, and that number was originally set to climb even higher. Hikari’s group arrived a few days earlier than in the original storyline. In that timeline, even Tanjiro’s team would barely survive this encounter, needing months of recovery afterward. 

But… 

For Uchiha Hikari, this was good news. After all, a chance to take down this many demons at once didn’t come often. 

“Tanjiro, picking up any demon scents?” 

“Yeah, up ahead, about a kilometer out. It’s strong!” 

“Zenitsu?” 

“…There’s a ton of people screaming over there. It sounds brutal. Maybe we should, y’know, head another way?” Agatsuma Zenitsu hugged his shoulders, trembling again. 

Gotta hand it to them—Tanjiro’s nose and Zenitsu’s ears were seriously impressive. In some ways, they were almost on par with the Hyuga clan’s Byakugan. Since Hikari hadn’t yet mastered using “ki” for wide-range sensing, her ability to track demons was actually a step behind theirs. 

“A kilometer… that’s close enough. Hop on, Bulma.” 

Hikari glanced at the blue-haired girl beside her. 

“Uh… gimme a sec!” 

Bulma pressed a button on her mini-bracelet, shrinking herself instantly. Hikari crouched down, extending a hand to catch the tiny Bulma as she hopped into her palm, then slipped her into the chest pocket of her jacket. 

Tanjiro, Zenitsu, and Inosuke: “???” 

Zenitsu finally lost it. 

“I don’t get it! How does a huge car just boom and vanish like that, and now people can shrink?! Hikari-san, Bulma-san, are you sure you’re human and not, like, some gorgeous yokai from a story who’s super good at tricking people?” 

“…Chill, you’ll get used to it.” 

Hikari waved him off with a calming gesture, then turned to Tanjiro. “Tanjiro, want me to take Nezuko? It might be a bit safer than keeping her with you.” 

“Are you going off on your own, Hikari-san?” 

Tanjiro glanced at the box on his back, hesitating. “Thank you for the offer, but I’ll pass. I want to protect Nezuko with my own strength. I don’t want to burden you.” 

“Fair enough.” 

Hikari thought for a moment, then added casually, “You’ve all got those half-Senzu beans I gave you, right? Eat them if things get dicey. If you run into an enemy you can’t handle, run. Be careful, and don’t die here.” 

With that… 

She formed hand signs. 

“Kage Bunshin no Jutsu!” 

Poof, poof, poof— 

A cloud of smoke burst forth, and four or five Uchiha Hikari clones appeared in the forest. The real Hikari handed out lightsabers and sealing scrolls to each clone. They only had three lightsabers—not enough for everyone—but Hikari had splurged at Konoha’s ninja tool shop, so each clone got a sealing scroll, with plenty left in her bag. 

Meanwhile… 

Tanjiro and the others stared, jaws dropped, at the scene. 

Zenitsu grabbed his hair, eyes practically popping out. “Tanjiro, Inosuke, you saw that, right?! It’s gotta be a yokai! No way it’s not! First shrinking, now cloning?! How can a human do this?!” 

“No, it’s a god.” 

Inosuke shook off Zenitsu’s grip on his shoulders, correcting him seriously. “Hikari-san and Bulma-san’s true identities have to be mountain gods. I heard legends like that when I lived in the forest.” 

“Pfft—” 

Hikari couldn’t help but laugh. 

To be fair, she and Bulma’s antics were pretty wild. Even in the modern world, someone who’d never seen Dragon Ball or Naruto might think this was some supernatural nonsense, let alone Tanjiro and the others, who lived in a relatively “ancient” era. 

Hikari didn’t bother explaining much. She waved to Tanjiro’s group, then, along with her shadow clones, soared into the sky. 

Bukujutsu! 

“…” 

At this point, Zenitsu gave up complaining. Flying was probably normal for a yokai, right? 

Beside him, Tanjiro took a deep breath and drew his blade. “Hikari-san has bigger things to handle. Let’s move, too. I smell blood up ahead—someone might be hurt. We need to get there fast!” 

… 

The mountain breeze swept through. 

Hikari’s real body rode atop the Somersault Cloud, surrounded by her shadow clones flying high in the sky. Including Bulma, six pairs of eyes scanned every direction, their long hair whipping in the fierce wind. 

The closest “Mother” demon to Tanjiro’s group was skipped by Hikari. It wouldn’t be cool to hog all the action, and since “Mother” wasn’t that strong, she’d leave her for Tanjiro and the others to practice on. 

Suddenly… 

Two figures in white robes with white hair, walking along the mountain path, caught Hikari’s attention. 

“Spider Family demons.” 

Whoosh, whoosh— Two shadow clones dove downward, while Hikari and the others flew deeper into Spider Mountain. 

New targets kept popping up. 

One by one, shadow clones peeled off. 

Finally, a cluster of stone buildings on a mountain ridge caught Hikari’s eye. In the clearing in front of them stood a towering, pitch-black figure with a spider-like face tilted upward, seemingly spotting Hikari in the sky. Its fanged mouth let out a low, beastly growl. 

“Bulma, close your eyes and hold on tight.” 

“We’re going down.” 

Hikari stood up on the Somersault Cloud. Her eyes flashed with the three-tomoe Sharingan as her fingers hit the switch on her protective gear. 

Flash! 

In an instant, a blinding light erupted, like a sun blazing in the sky, bathing the surrounding forest in radiance. High above with no cover, even people kilometers away could see the glowing orb suspended in the night sky through layers of trees. 

Then, a dark red light pierced through the glow. 

The next moment… 

The light source transformed into a shooting star, plummeting straight toward the ridge below! 

“Ryusei Seigun!!!” 

Chapter 53: Have You Ever Seen Me at My Peak? 

At that moment… 

A meteor trailing crimson flames tore through the deep night sky, crashing precisely in front of the stone house! 

In an instant, the impact from the heavens unleashed a torrent of force, forming milky-white shockwaves that blasted the surrounding air away! Within a dozens-meter radius, a massive vacuum zone formed! 

Serpentine cracks snaked outward in all directions, and the sound of collapsing stone walls echoed in a chaotic chorus! 

BOOM! 

Dust filled the air! 

Amid the clamor, Uchiha Hikari extinguished the light source on her protective suit. Shielded by the skeletal frame of Susanoo, she gently touched down, scanning her surroundings. 

The cluster of stone buildings she’d seen from the sky was gone. In its place lay a field of shattered ruins. 

The spider-faced “Father” had vanished as well. 

All the demons in the Spider Family were taken in and raised by the true Lower Rank Five, Rui. By consuming Rui’s blood, they gained spider-like Blood Demon Arts similar to his. Among them, “Father” was the closest to Rui in strength, boasting extraordinary physical power, regeneration, and a body as hard as stone. He could even molt to further enhance himself. 

If the Ryūsei Senkō (Meteor Flash) she’d just used had been as powerful as the one against Danzo, even a literal rock would’ve been ground to dust. 

But… 

Right now, Uchiha Hikari only had one-fifth of her chakra left. Plus, she’d deliberately offset her landing point slightly. So, “Father” was only torn into pieces by the sword light and buried under the rubble. He’d probably crawl out soon. 

“Little… Hikari?” 

A rustling sound came from the pocket of Hikari’s jacket. 

Bulma, trembling, gripped the edge of the pocket and peeked out, her face pale. “Are we… still alive?” 

“…I’d say so.” 

Hikari replied softly. 

She’d been keeping an eye on Bulma during the descent, shielding her with one arm and wrapping some chakra around her chest to prevent Bulma from being flung out of the pocket. Still, the freefall experience was clearly a bit too thrilling. 

“Um… Hikari, can I come out now?” 

Bulma hesitated, her face shifting from pale to red as she mumbled, “I… need to change my pants…” 

“…” 

Hikari froze for a second, subtly sniffing the air and catching Bulma’s meaning. But her tone was firm. “No.” 

“Huh?” 

“Because the fight’s not over… Something’s coming.” 

As Hikari’s words fell… 

A sharp, grating sound erupted from the ruins ahead. 

First, a massive arm burst from the debris, followed by a towering, dark figure that slowly pushed aside the stone slabs. Standing up amidst the collapsed ruins, the figure was four or five meters tall, like a small mountain, radiating suffocating pressure. 

—Though the pressure might’ve been more convincing without the massive, still-unhealed gashes carved by sword energy across its body. 

Bulma instantly shrank back, clutching the inside of the pocket and trembling. 

Hikari, however, gave “Father” a brief glance before shifting her gaze to the side. 

There, in the woods to the right of the clearing… 

At some point, a short, white-haired boy in white clothes had appeared silently, staring at them with cold, murderous eyes, an almost imperceptible killing intent radiating from him. 

Hikari tilted her head. “Lower Rank Five, Rui?” 

No response. 

After a brief stare-down, Rui spoke coldly, “You… deserve to die.” 

“You destroyed the home our family depends on. You’ll pay for it. Father, kill her!” 

“ROAR!” 

The battle erupted in an instant. 

On Rui’s command, “Father” let out an explosive roar, hurling a several-meter-long stone slab toward Hikari. He charged forward, his massive fist tearing through the air, aiming to crush her into a pancake! 

Facing the twin gusts of force, Hikari gripped her short blade and took a deep breath. 

“Water Breathing, Fourth Form: Striking Tide!” 

Her blade danced! 

In that moment, blue water ripples appeared in the air. As Hikari twisted her waist, the ripples became a tidal wave of continuous slashes, meeting the incoming slab. In a blink, the slab shattered, and her blade, unchecked, sliced toward “Father’s” oncoming fist! 

CLANG! 

The blade met the fist, and Hikari instantly felt a surge of overwhelming force through the edge. But her expression remained calm, even composed enough to switch breaths. “Thunder Breathing, First Form: Thunderclap and Flash!” 

A faint golden arc sparked, then stretched sharply! 

With Thunder Breathing active, Hikari’s short blade accelerated, cleaving through “Father’s” fist, splitting half his arm and even the bones within! But the blade, unable to withstand such intense force, snapped in half mid-strike. 

CRACK! 

As the blade broke, Hikari leaped back, swiftly retreating from “Father’s” attack range. 

The next second, his massive fist slammed into the ground, leaving a deep crater! 

“Huff…” 

The distance between them widened rapidly. 

“Father” roared in pain, ignoring the fountain of blood gushing from his arm. He yanked out the half-blade embedded in his bone and hurled it at Hikari. She casually deflected it with the remaining half of her blade, sending it flying. 

Looking at the broken weapon in her hand, Hikari frowned slightly. 

“Guess the forging at Konoha’s ninja tool shop isn’t that great. It can’t even handle this level of impact.” 

“Next time I’m back, I’ll need to find a proper weapon… Orochimaru’s Kusanagi Sword seems decent. Maybe I can ask him for one?” 

On the other side… 

Rui’s eyes narrowed, as if he’d already seen the outcome. “I thought you were a Hashira from the Demon Slayer Corps. Turns out you’re just bluffing… Father, she’s yours. By dawn, I want her corpse hanging at the foot of the mountain.” 

“…” 

A brief silence. 

Hikari sighed softly. “I was planning to test some new moves on you guys, but… forget it. Hey, Lower Rank brat, let me ask you—have you ever seen me at my peak?” 

“?” 

Rui paused, turning back with a puzzled look. 

Then… 

His eyelids twitched violently as his gaze met a pair of blood-red eyes! 

“Genjutsu: Shackling Stakes!” 

Chapter 54: What Do You Think Life Is? 

Rui’s eyes trembled as a horrifying realization hit him— 

“My body…” 

He couldn’t move?! 

At the same moment, Uchiha Hikari unleashed a “Kasegui no Jutsu” on the spider-faced “Father.” Caught mid-step with his fist raised, he was frozen in place. No matter how desperately he flexed his muscles to break free, all he could manage was a furious, helpless roar. 

Then… 

Hikari turned, drawing a second short blade from behind her. 

This time, the three-tomoe Sharingan in her eyes spun silently. As her pupil power surged, a dark red aura flared around her, forming the first stage of Susanoo, enveloping both her and the blade. The two-foot-long sword seemed to stretch nearly double in length, its gleaming edge now faintly coated in dark red. 

Hikari stepped forward slowly, raising the dark red longsword bit by bit until it was level with her shoulders. 

“What is that?!” 

Rui’s eyes widened, alarm bells screaming in his head! 

In that instant, the binding force holding him seemed to vanish for a split second. Without time to think, Rui seized the chance and activated his Blood Demon Art: 

“Blood Demon Art: Cutting Thread Cage!” 

A web of steel-like threads materialized in the air, densely packed, blocking the space between them. 

Hikari’s toes tapped the ground, and she accelerated. 

As she passed through the Cutting Thread Cage, her figure didn’t even pause for a moment. The Susanoo cloaking her tore through the “spider threads” like paper, and she swung a horizontal slash at Rui, dozens of meters away! 

“Hundred-Eight Sections: Red Flame Slash!” 

In that moment, the dark red longsword grazed the air, igniting crimson flames that swept forward in a massive arc! 

Shing—!! 

If someone were watching from above, they’d see a fiery semicircle over ten meters long unfurling before Hikari! 

The blade hadn’t even reached its target. 

Yet the sword’s aura had already spread, engulfing an area dozens of meters around!! 

Rui didn’t even have time to finish raising a block before the slash sent him flying high, his body splitting into pieces mid-air. Each fragment burst into flames, crashing into the forest behind like cannonballs! 

In that fleeting moment of being hurled back, Rui’s dark golden eyes—marked with “Lower Five”—locked onto the blazing greatsword in Hikari’s hand. The sight seemed to drag up a distant memory: 

“…A Hissatsu Blade?!” 

“Hm?” 

Hikari raised an eyebrow. 

Of course, she knew what a Hissatsu Blade was—one of the three key elements in the Demon Slayer world. It was said to manifest when a Nichirin Blade reached a certain temperature, making the entire blade appear to burn. Striking a demon with such a blade could mimic the effects of “Sun Breathing,” leaving wounds that were nearly impossible to heal, as if scorched by the sun itself. 

On Muzan, the Demon King, there lingered scars from a Hissatsu Blade left by Tsugikuni Yoriichi centuries ago, wounds that still tormented him to this day. 

When Hikari swung that sword, she hadn’t been thinking about Hissatsu Blades. But now, looking at it… 

The dark red blade, wreathed in vivid crimson flames, did bear a striking resemblance. 

“The appearance…” 

A playful idea sparked in Hikari’s mind as she smirked. 

… 

Boom—!! 

Rui’s body hurtled nearly a hundred meters. 

After smashing through several trees, his momentum finally slowed, and he crashed heavily into the ground. 

A demon’s body was far tougher than a human’s, especially for the Lower Rank Five. Even so, that single horizontal slash had torn him apart. His bones—probably a hundred or two—were shattered, his flesh reduced to a pulpy mess, and his once-white kimono was now stained a glaring red. 

Though his potent regeneration was rapidly repairing the damage, Rui was left confused and enraged. 

“That human… what is she?” 

“Red eyes, some eerie ability that paralyzes people, and a burning Hissatsu Blade…” 

Was this some new technique developed by the Demon Slayer Corps? 

He couldn’t wrap his head around it. 

“Father… where’s Father? Is he already dead? Why isn’t he coming to save me?! Of course… worthless family members like him don’t deserve to live! They should just die like those filthy humans!” 

His thoughts still in chaos, Rui heard footsteps approaching. 

Struggling to prop himself up, he looked toward the ridge. 

And then… 

“?!” 

It was, of course, Uchiha Hikari. 

But she looked different now. 

Under the moonlight, she wore a red haori that hadn’t been there before. Her long, jet-black hair had somehow turned crimson, swaying gently in the night breeze. And on her smooth forehead, a dark red pattern had appeared, vivid as flames. 

“That’s…” 

“A Demon Slayer Mark?!!” 

Rui’s pupils shook. 

Under his gaze, Hikari raised her short blade. Vermilion flames danced along the edge, the “Hissatsu Blade” reappearing! 

“So, Lower Rank brat, you seem to love playing this little game of house, don’t you?” 

Her cold voice rang out slowly, like a sharp knife grazing Rui’s ears. 

“Gathering a bunch of unrelated demons around you, pretending to be a family, manipulating them to slaughter any humans who wander into the village, reveling in the power over life and death… that stuff’s fun for you, huh?” 

Hikari’s face was expressionless, her words steady and unhurried. “But you know what? I don’t think it’s fun. Not one bit. And it’s definitely not funny.” 

“What do you think…” 

“…life is?!” 

“!!!” 

In that moment, Rui was utterly petrified. 

Images etched deep in his DNA surged from the Muzan cells within him, flooding his mind. 

“These are… Lord Muzan’s memories…” 

In a daze, the figure of a taller male swordsman appeared in Rui’s vision, speaking the same words in the same tone. The only difference was the red sun earrings he wore. 

“Lord Muzan is… afraid?!” 

Yes. 

At that moment, a wave of fear welled up from the Muzan cells in Rui’s body, rapidly spreading through every limb. For the first time in decades on Spider Mountain, as a member of the Twelve Kizuki, he felt his soul tremble! 

“No, this can’t be… I’m one of the Twelve Kizuki! How could a human scare me…?” 

Rui desperately tried to stand, but his body wouldn’t stop shaking. It was the primal fear of prey facing a predator! He couldn’t even manage something as simple as moving a finger! 

Across from him… 

Hikari raised her short blade, taking a deep breath. “Sun Breathing… Seventh Form: Solar Flare Thrust!” 

Chapter 55: About Tsugikuni Yoriichi Reincarnating as a Girl 

Before the words even settled… 

Uchiha Hikari launched another thrust. 

As she moved, her short blade’s edge shimmered with rings of blazing flames—a scene eerily identical to the legendary swordsman Tsugikuni Yoriichi from centuries ago! 

“AAAHH!!” 

Muzan’s cells quivered violently! 

That indescribable terror coursed through his blood, reaching Rui and making him feel it just as intensely! 

At the critical moment, driven by an overwhelming survival instinct, Rui frantically summoned every ounce of power in his body, his ten fingers interlocking. “Blood Demon Art: Cutting Thread Rotation!” 

Countless spider threads materialized, weaving the surroundings into an inescapable web. A massive vortex of threads formed a cocoon, hurtling toward Uchiha Hikari! 

Faced with this desperate, all-or-nothing attack… 

Hikari’s response was a simple, unremarkable circular slash. “Sun Breathing… First Form: Waltz!” 

A flash of light. 

With a perfectly round arc, Rui’s final, full-powered move was effortlessly dismantled. The blazing blade and its ring of flames passed through, and every thread melted like snow under the sun. Then, a mix of black and red flames trailed her blade as it sliced through Rui’s body, cutting him into pieces in an instant. 

Agony, like being burned by the sun itself, spread rapidly. The severed wounds showed no sign of healing. 

“As expected…” 

It was Sun Breathing! 

Rui sank into despair, his mind replaying a montage of his life. 

But just then, the black flames began to fade. In their place, black runes spread from Hikari’s hands, swarming over Rui’s body like tadpoles. With a low murmur of “Five Elements Seal,” Rui’s fragmented body was sucked into a scroll, securely sealed away. 

After finishing this… 

Hikari coldly scanned her surroundings, confirming Rui’s presence was completely gone. Then, she formed a hand sign and released her Transformation Jutsu. 

That’s right. 

She didn’t actually know Sun Breathing. 

The red hair, the forehead “markings”—all of it was crafted with Transformation Jutsu. The “Waltz” and “Blazing Sun Thrust” were her approximations based on her knowledge of Demon Slayer’s plot. They were just a thrust and a circular slash, basic sword techniques she could mimic well enough. 

As for the “Nichirin Blade” effect… 

It was merely Fire Release, with a tiny bit of Hawkins added for good measure. 

The disguise wasn’t perfect, but it was enough to fool Muzan. 

After all, if just Tanjiro’s hanafuda earrings could scare Muzan into avoiding him personally, then what kind of psychological pressure would someone with Yoriichi’s hair color, markings, a Sun Breathing sword style with over 70% similarity, and the ability to inflict unhealable wounds exert on Muzan? 

Hikari was very curious. 

“Just as I thought, Amaterasu’s lethality against demons far surpasses regular Fire Release. It’s probably even stronger than true Sun Breathing. If I’d held back Amaterasu for ten seconds longer, this guy would’ve been incinerated completely…” 

She didn’t really want to kill Rui. 

After all, test subjects like the Twelve Kizuki were rare—each one lost was one less. Until she could capture Muzan, the source capable of mass-producing demons, she couldn’t afford to waste them. 

As the final rune vanished, Hikari tucked the scroll into her jacket, tossed aside the short blade nearly melted by Amaterasu, and returned to “Father.” She sealed the still-immobilized demon as well. 

“…All done!” 

Only then did Hikari stretch lazily and call Bulma out. 

“…Gulp.” 

Back to her normal size, Bulma surveyed the clearing and forest, scorched by flames, sword energy, and Susanoo. She swallowed hard. “Hikari, what happened here? This can’t all be from your fight with those two demons, right?” 

“Mm.” 

Hikari nodded. “I meant to keep things under control, but I haven’t fully mastered the Breathing Techniques I got from Tanjiro and the others. Got a bit carried away.” 

“A bit carried away…” 

Bulma gave Hikari a complicated look. “Sure, I believe you.” 

But that wasn’t the priority. For Bulma, the most pressing matter was… 

“Uh… Hikari, could you keep watch outside? I need to clean up and change clothes. I’ll be quick!” 

With that, her face flushed, Bulma tossed out a Capsule, conjuring a small house in the clearing. She darted inside to shower and change. 

The sound of running water echoed from the room. 

Hikari clasped her hands behind her head, flopping onto the soft grass and gazing at the night sky. 

“Around this time, the Hashira from the Demon Slayer Corps should be on their way, right?” 

“I wonder if Kibutsuji Muzan saw my performance just now. If he did… his face must be priceless.” 

… 

In another dimension, Infinity Castle. 

A lab table covered with various instruments lay toppled, glassware shattered across the floor. 

A black-haired young man with plum-red eyes clutched his arms, curling into a ball. 

Overwhelmed with tension, his pale face flushed red, veins bulging on his neck, pupils contracted to slits. His entire being radiated a dark, oppressive aura, causing the wooden floor around him to creak and splinter, teetering on collapse. 

“It’s him… It’s him!” 

“That appearance, that pain… No mistake… It’s that man’s Sun Breathing!” 

“Why? Why! Why isn’t he dead?!” 

“AAAHHH—!!!” 

In that moment, Muzan’s five brains nearly shut down. Only two images flickered in his mind: the red-haired man from centuries ago and the red-haired girl he’d “seen” through Rui. In a daze, the two figures began to overlap, especially with her words, “What do you think life is?” ringing in his head. It cemented one truth for Muzan— 

It was him! 

Tsugikuni Yoriichi! 

The human who terrified him had crawled out of his grave!! 

And… he’d even reincarnated as a girl!! 

After a long time… 

Muzan finally regained a sliver of composure. He lifted his head and let out a hysterical roar toward the figure on the high platform. 

“Nakime!!” 

An indescribable pressure erupted, shattering dozens of floating wooden rooms around him. Even the kimono-clad woman with long hair obscuring her face, seated on the platform and clutching her biwa, felt the force. Her hands gripped the instrument so tightly that veins popped, and thick blood welled up in her throat. 

“…Kokushibo! Summon Kokushibo to me!” 

“Now!!” 

(Chapter End)