Demon Slayer: Dragon Hashira#30/31: Lower Rank Four—Mukago, The Demon Who Hunts Demons

Butterfly Mansion

"He's completely exhausted. After reviving Lady Ruka, he didn't rest properly for days. Then fighting Shinjuro-san drained the last of his energy. He needs extensive recovery time."

After examining Kaidō, Shinobu reported the situation to everyone.

Hearing this, they all sighed with relief.

"Look at you... couldn't go easier on him?? If something happens to this child, don't expect to see me again!" Ruka grabbed Shinjuro's ear, twisting it.

"Ow ow ow! Dear, I'm sorry! Please, not so hard—everyone's watching! Kyojuro, Senjuro, help me!"

But Kyojuro and Senjuro pretended not to hear, turning to Shinobu instead. "In that case, let young Kaidō rest. I'll patrol his territory temporarily."

"I'll help too! I'll bring him snacks to help him recover faster." Senjuro added.

Shinobu nodded, then addressed Shinjuro. "Shinjuro-san, though you're the former Flame Hashira, I must say this: Kaidō-kun paid an enormous price to revive my sister. Then he revived Lady Ruka. Plus, he's activated his Demon Slayer Mark. You know what that means. He did all this hoping you'd return."

"Sigh... this is my fault. But I won't resume the Flame Hashira position—that belongs to my son, Kyojuro. However, I will return to train other Corps members." Seeing Ruka reaching for his ear again, Shinjuro quickly finished his statement.

"Good. As long as you understand." Ruka walked to Kaidō's bedside, gently stroking his face.

"This child must have suffered so much when he was younger. Shinobu-san, please take good care of Kaidō. I have much to discuss with my family. I'll visit him in a few days."

"Don't worry—I will."

"Kyojuro, Senjuro, let's go home. Let Kaidō rest. We'll visit in a few days. And you, Shinjuro—you owe me a full explanation!"

"Yes, Mother." Kyojuro and Senjuro replied in unison.

"Of course, Ruka! Hahaha!"

"Well then, we'll take our leave as well. Shinobu, we're entrusting Kaidō to you."

"Yes, Master."

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Butterfly Mansion

"Shinobu-nee, I'm begging you—please let me go on missions! I've been resting for three days already! I'm completely fine! Please, please!" Kaidō pressed his palms together pleadingly.

"Absolutely not! I need to verify you've fully recovered first. Otherwise I won't feel comfortable letting you go. The Master, Lady Ruka, and my sister all entrusted me with taking care of you!"

"But look—I was just exhausted, not injured! I'm totally fine!"

"I'm the doctor here, so I make the calls. If I say you haven't recovered, then you haven't!"

"Shinobu-nee, gentler, gentler! Can't we talk this out? Ow!" Shinobu had grabbed his ear and was twisting it mercilessly.

Ever since Kanae's revival, Shinobu had dropped her facade and returned to her true, lively self. Which was exactly what Kaidō had wanted all along.

"Oh my! The Butterfly Mansion is so lively today!"

"Sister."

"Kanae-nee!"

"What are you two doing? This looks fun!"

"Kanae-nee, I want to go on missions! Please!"

"Permission granted!"

"But Sister—"

"It's fine, don't worry, Shinobu!"

"However, Kaidō-kun, if you want to go on missions, you need to agree to one condition."

"What condition?"

"No more of that! You need to think about yourself for once, understand?"

"Alright, Kanae-nee. I promise!"

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"CAW CAW! East-southeast! East-southeast! Suspected demon sighting!" Kuroha perched on Kaidō's shoulder.

"Sigh... feels like so much has happened lately. Whatever—forget it. Time to catch some demons and blow off steam!"

[Host, are you certain it's 'blowing off steam' and not 'psychological warfare'?]

'Not my fault those demons have such fragile mental defenses.'

'System, what would happen if I used the Heart of Revival on Yoriichi Tsugikuni?'

[Host, I advise against such unrealistic fantasies. Even if revival were possible, the cost would be astronomical. Yoriichi lived during the Sengoku period. Reviving him would be pure delusion.]

'But hypothetically, what would it cost?'

[Analyzing... Analysis complete! Revival cost: Heart of Revival x10, 100% Interdimensional Energy, Host must sacrifice 300 years of lifespan.]

'Yeah, never mind. Reviving Yoriichi really is pure fantasy! Three hundred years of my life? Hard pass!'

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That Night—Nishino Village

'Hm? Where's that smell of blood coming from?' The moment he entered the village, a faint metallic scent hit his nostrils. Not overpowering, but definitely there. Following the trail, he arrived at the mountain behind the village.

'The smell's getting stronger here. Something's definitely nearby.' He lowered his fox mask, drew his greatsword, and began searching the area.

After a brief search, he found the source—a cave entrance.

'The blood's coming from in there. The demon must be hiding inside.'

Staring into the pitch-black interior, Kaidō opened the System Lifestyle Shop, purchased a hand lantern, and ventured into the darkness.

The deeper he went, the stronger the scent became. Then he heard strange echoes from the cave's depths—the unmistakable sound of chewing.

After several minutes, he reached the end. A female demon crouched over a corpse, feeding. Sensing someone behind her, she immediately went on guard and whirled around, revealing her face.

Small frame. Shoulder-length white hair. Two thick red lines symmetrically painted on each side of her face. Two small spiral horns protruding from her forehead. Red fur-collared kimono. Red irises with white pupils. The kanji for Lower Four carved into her left eye.

"Lower Rank Four—Mukago."

"How—how do you know my name?? Are you a Demon Slayer?" Mukago shrieked.

"Whatever! Even if you're a Demon Slayer, as long as you're not a Hashira, I can devour you! Blood Demon Art: Vine Manipulation!"

Dozens of vines erupted from all directions, binding Kaidō completely.

"You're so weak! I was worried for nothing!" Mukago approached confidently and removed his fox mask. Seeing his face, she found him unexpectedly adorable and couldn't resist pinching his cheek.

"You're so cute! I almost don't want to eat you! Hey, hey—why don't you become a demon instead? I'm so lonely by myself. You can keep me company!" She kept squeezing his face.

In reality, Mukago had been standing frozen in place ever since she'd turned around. The instant she'd spun to face him, Kaidō had activated Demonic Eye, trapping her in an illusion.

The system chimed in his mind.

[Host, now that she can't move, shouldn't you do something? She may be a demon, but she's pretty cute. (◕‿◕✿)]

'You're absolutely right. I should do something—otherwise I'd be wasting Demonic Eye. Hehe!'

[So you're going to...]

'You thinking what I'm thinking?'

[Who could refuse such adorable demon?]

'My thoughts exactly!'

Kaidō slowly approached Mukago. Still trapped in the illusion, she believed she'd successfully bound him. He reached out and gently touched her face. "You're a pitiful girl. But if I don't do something now, I'd be letting myself down. So... sorry about this!"

He retrieved a Collection Card from his system inventory—a previous reward that could transform any Lower Rank demon into a card. Placing it on Mukago's forehead, light flashed. She transformed into a card, which he promptly stored in his inventory.

'System, why do I get the feeling some people thought I was about to do that to Mukago?'

[Indeed! (◠‿◠✿)]

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Seeing Kaidō emerge from the cave, Kuroha flew over and landed on his shoulder.

"The demon here's been eliminated. It was a Lower Rank."

"Understood! CAW!" Kuroha flapped his wings and flew toward Corps Headquarters. Kaidō shrugged—let the crow announce it. Didn't matter to him.

He pulled out the Collection Card to examine the captured Mukago. The instant he saw the image on the card, several veins popped on his forehead.

'SYSTEM! EXPLAIN THIS RIGHT NOW! Did you do this on purpose?? Why does Mukago's expression look so—'

[Rest assured, Host. The system is functioning normally. This is simply how Mukago appears.]

'Like hell I believe you! This system was definitely a pervert system in a past life!'

The card showed Mukago with her mouth open, tongue out, panting, face flushed red, hands positioned suggestively on her chest.

"Is this system even remotely appropriate??" Kaidō rubbed his forehead helplessly before storing the card back in his inventory.

Over the following days, Kaidō patrolled his territory. Any demon he found got strung up and beaten. Demons that ran got decapitated immediately. His zone had become eerily peaceful.

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"So many wisteria trees here. Perfect—I haven't slept properly in days. I'll nap here for a bit and patrol again tonight." He yawned, sitting down with his back against a wisteria tree for a quick rest. Kuroha nestled in his lap.

Creak.

A door carved with wisteria patterns opened at the tree's center. An elderly woman emerged with a broom, sweeping the entrance. Noticing Kaidō resting under the tree, she returned inside, fetched a blanket, and draped it over him. Then she stood nearby, watching over him until he woke.

Perhaps the motion of covering him disturbed his sleep. Kaidō's eyes opened. Seeing the elderly woman, he relaxed—her kimono bore the wisteria crest marking her as part of a Wisteria Crest House.

"Sorry for startling you, ma'am."

"Honored Demon Slayer, please come inside and rest properly."

"Thank you for your hospitality."

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"I've prepared a meal for you. Please follow me."

"Thank you—I haven't eaten much these past few days while fighting."

"You're too kind. This is my duty."

The meal was generous: a bowl of white rice, fried shrimp tempura, and a large bowl of miso soup.

"Please enjoy your meal. I'll wait outside. Call if you need anything."

"Thank you."

After eating, he took a bath.

"Honored Slayer, I've left clean clothes by the door. Your uniform will be ready tonight." The elderly woman called from outside the bathroom.

"Thank you very much."

That Night

After resting all day, Kaidō changed into his freshly washed uniform, strapped on his greatsword, and adjusted his mask. At the Wisteria House entrance, the old woman struck two flints, creating sparks before him.

Kaidō thanked her and waved goodbye.

"May fortune favor you in battle."

<><><><><><><><>

Somewhere in the Forest

Four low-level demons were desperately fleeing. Behind them, a demon slayer casually leaped between tree trunks in pursuit.

"Run faster! Don't let that demon slayer catch us!"

"Sob sob... I just wanted to eat a few humans! Why did I have to run into him??"

"Shut up and keep moving! If he catches us, we're dead! That demon slayer is terrifying—his methods of torture are horrific! He's a complete monster!"

"I don't want him to catch me! He's not even human!"

After running for miles, the four demons stopped, gasping for air.

"We ran so far... we must've lost him. Huff huff..."

"That was terrifying! That demon slayer is absolutely terrifying!"

"This area isn't safe anymore. Let's hunt humans somewhere else."

"He's not human!"

While the four demons conversed, an unexpected voice spoke right beside them.

"Keep running. Come on, I was having fun. Don't make me lose interest so quickly."

"Who's there?? Show yourself!" The four demons instantly broke into cold sweat, pressing their backs together.

"He's up there!"

One demon pointed at a tree.

Kaidō sat on a branch—with his fox mask tilted on his head.

"Why'd you stop running?" Kaidō sat on the branch, mask askew, greatsword on his back, pale legs dangling and swinging back and forth. He took a bite from an apple in his hand.

"Whatever. This is boring. I'm done playing. Time to send you off." He jumped down, apple in one hand, drawing his greatsword with the other.

"Screw it! We'll fight this monster to the death!" All four demons charged simultaneously—one last desperate gambit.

"Water Breathing, Third Form: Flowing Dance."

Kaidō's body moved like water at incredible speed. His movements were so swift that only afterimages remained in his wake. All four demons were decapitated instantly.

As their heads flew through the air, they all uttered the same words: "Finally... free..." Then heads and bodies dissolved into nothing.

"Tch. No fun at all. Better find other demons to practice on." He sheathed his greatsword and continued walking, munching his apple while humming a tune, searching for more demons.

Watching this, the system thought: 'Why does Host act like a completely different person compared to his previous life??' Though it wisely kept that observation to itself.

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Three Months Later

"CAW CAW! The Master summons you! Return to Headquarters immediately!" Kuroha relayed Kagaya's orders.

"Understood. Heading back now."

'System, monthly check-in.'

[Ding! Check-in successful!]

[Congratulations! Host has acquired skill: Sword Flight.]

[Sword Flight: Consume mental energy to fly on your sword. More energy = faster speed. Can also control the greatsword for long-range attacks. Every boy dreams of flying on a sword.]

"Holy crap—Sword Flight! This is going to be awesome!" Kaidō was thrilled. He'd dreamed of sword flight in his previous life, but it had always been pure fantasy. Now it could actually happen!

The past two months' check-ins had also been useful: Clone Talismans and an Explosive Gun.

Clone Talismans—self-explanatory.

Combined with his previous ten, he now had twenty total.

[Explosive Gun: Fires explosive rounds highly effective against demons. Even Upper Ranks are vulnerable.]

'Don't really use guns, but I'll save it. Might be useful later. First, I'm testing Sword Flight! This has been my dream forever, and now it's finally real!'

He injected mental energy into his greatsword. The blade slowly rose. Since his greatsword was quite wide, Kaidō simply sat on it cross-legged, legs dangling. Kuroha, curious, landed on his shoulder to see what would happen.

WHOOSH!

They shot forward, leaving only a few black feathers floating in the air.

"CAW—!" Kuroha's talons gripped Kaidō's clothes desperately, cawing frantically.

"WOOHOO! THIS IS AMAZING! HAHAHA!" His long white hair streamed behind him in the wind as he soared toward Corps Headquarters on his flying sword.

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Demon Slayer Corps Headquarters

Kaidō flew into Headquarters on his greatsword. Corps members gaped in amazement at the sight.

"Isn't that Dragon Hashira-sama?? He's flying! Do Nichirin blades have flight capabilities now?" One swordsman tried placing his blade on the ground and sitting on it.

His butt hit the dirt immediately.

"Ow! That hurt! My ass... ow~"

"Haha! You really think you can do what Dragon Hashira-sama does? I heard he's from a mysterious ancient Eastern family with secret techniques. Being able to fly isn't strange at all. Plus, I heard some other things about Dragon Hashira-sama."

"What things? Tell me!"

"You know how Flower Hashira-sama at the Butterfly Mansion came back to life? Dragon Hashira-sama used his family's secret technique—trading his own lifespan to revive her! He also brought back the former Flame Hashira's wife the same way."

"No way?? Dragon Hashira-sama is that incredible?? Truly admirable. I also heard he treats everyone kindly—no ego whatsoever, completely egalitarian. Seems it's all true. Plus, I heard he challenged the former Flame Hashira!"

"Oh yeah—a few months ago when Dragon Hashira challenged the former Flame Hashira, I was there to watch!"

"Tell me everything! I was on a mission and missed it. Such a shame."

"Listen carefully then. That day..."

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Ubuyashiki Estate

"Dragon Hashira-sama, Father asked me to wait for you here. Please follow me." Hinaki Ubuyashiki stood at the entrance.

"Thank you for your trouble."

Following Hinaki into Kagaya's room, Kaidō found Giyu and Shinobu already kneeling inside.

"Child, you've returned."

"Master, why have you summoned me?"

"Mount Natagumo has suspected demon activity. Many of our young swordsmen went to investigate—all were wiped out. It may be one of the Twelve Kizuki. We need Hashira support. I'd like you to go with Giyu and Shinobu to investigate."

"Yes." The three responded in unison.

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Mount Natagumo

Giyu, Shinobu, and Kaidō moved swiftly through the forest.

"Wouldn't it be nice if demons and humans could coexist peacefully? Don't you think, Tomioka-san?"

"As long as demons eat humans, that's pure fantasy." Giyu's reply was blunt.

"I see! What about you, Kaidō-kun? What do you think?"

"When I first met Master Urokodaki, he asked me something similar. I told him: if it's an evil demon, I'll kill it without mercy. But if it's a good demon, I'll let them live out the rest of a human lifespan in peace."

"Why do you say that?" Shinobu looked puzzled. Even Giyu seemed curious.

"If we can't distinguish between good and evil demons, why are we demon slayers at all? Imagine someone forced to become a demon through no fault of their own—they never hurt anyone, they even helped people. But they get killed just for being a demon. Does that demon deserve to live or die? Now flip it: a human who pretends to be good but secretly helps demons slaughter innocent people for profit. No different from a demon himself. Does he deserve to live or die? If we can't tell good demons from evil ones, what does that make us? Everything has cause and effect. Immortality sounds nice, but you lose so much more. Watching everyone you love die one by one while you remain—what kind of suffering is that?" Kaidō voiced his honest thoughts.

Both Giyu and Shinobu fell silent, deep in contemplation.

"We're here—Mount Natagumo. Let's split up." Kaidō surveyed the mountain before them, lowered his mask, and flew deeper into the forest on his greatsword.

"I'm actually jealous of Kaidō-kun! Well then, time to get moving. Do your best, Tomioka-san!"

"Mm." Giyu's expression remained blank as he entered the mountain.

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After entering Mount Natagumo, Kaidō surveyed the area. Suddenly, thunder-like rumbling echoed in the distance.

'That direction must be Zenitsu Agatsuma. No surprise—someone who's perfected Thunder Breathing's First Form to its absolute peak. Looks like he's already dealt with Spider Demon Brother.' Kaidō flew toward Zenitsu's location.

Arriving at his destination, he found a small house suspended in midair by spider threads. Zenitsu lay sprawled on top.

Just as described: yellow hair, Corps uniform with a yellow haori featuring triangular patterns, rounded eyebrows, golden-blonde mid-length hair.

Zenitsu's hair was originally black. During training with his mentor Jigoro Kuwajima, terrified of the hellish regimen, he'd climbed a tree to escape. Lightning struck him, changing his hair color permanently. Extremely cowardly and weak-willed, constantly convinced he's about to die.

To avoid dying single, he constantly bothers girls, begging them to marry him.

Kind-hearted at his core, willing to stand up for friends and girls when it matters. Fell for Nezuko Kamado at first sight. Obsessed with girls but often gets rejected for being too clingy—even demon Nezuko isn't exempt from his attention. Though usually cowardly and selfishly demanding protection, he steps up in critical moments to protect children and his friends' precious things. Fundamentally a gentle person.

Possesses exceptional hearing—can hear people's inner voices and distinguish humans from demons by sound alone.

Zero confidence in his abilities as a swordsman. Fears and avoids fighting demons. However, when stressed to his absolute limit, he falls asleep and enters a semi-awakened state, unleashing his true formidable power.

Approaching Zenitsu, Kaidō asked, "Yo, Zenitsu. You okay?"

"She's so beautiful... like... like a white fairy!" Zenitsu stared at the masked, white-haired figure in awe.

"Still talking—situation's not terrible. You used Breathing to slow the poison's spread. Well done. Hang in there, don't give up! I'll take you to Shinobu for the antidote." He hoisted Zenitsu onto his back and descended on his greatsword.

'Don't give up!' Those words echoed through Zenitsu's mind repeatedly.

"I just had a dream!" Zenitsu spoke from Kaidō's back.

"Oh? What kind of dream?"

"A happy one. I became strong—stronger than anyone. I helped countless weak people who'd lost their way. Everything Gramps taught me wasn't wasted. I became strong thanks to him and helped so many people. Gramps kept telling me... don't give up..." Zenitsu passed out.

'A life flashing before his eyes?'

Kaidō glanced back at the unconscious Zenitsu. That dream sounded like the memories people see when death approaches.

Soon, he found Shinobu.

Approaching her, he set Zenitsu down. "Shinobu-nee, this kid took down that Spider Demon but got poisoned. Could you make him an antidote?"

Shinobu examined Zenitsu briefly. "He used Breathing to slow the poison—lucky kid. I'll prepare an antidote right away."

"I'll leave him to you. I'm going to check elsewhere."