Demon Slayer: Dragon Hashira#48/49: Kaidō: Muzan, I'm Coming for You! Retsuki Seen Completely Exposed.

Butterfly Mansion—Courtyard

"Listen up, brat! If you lose my blade again, I'll never forgive you!" Hotaru Haganezuka jabbed his finger repeatedly into Tanjiro's face, punctuating each word with a poke.

"Y-yes, I understand. Thank you..." Tanjiro's expression was utterly helpless as he nodded frantically.

"And this!" Haganezuka shoved a large wooden case into Tanjiro's arms. "When Kaidō wakes up, give this to him. I reforged his greatsword!"

The weight nearly knocked Tanjiro off balance.

"Tell him that considering he's sent me mountains of mitarashi dango, I'll overlook him breaking the weapon I forged this time." Though Haganezuka's words sounded angry, Tanjiro's nose picked up something different—genuine concern for Kaidō beneath the gruff exterior.

After all, Kaidō was a Hashira. Forging weapons for the Hashira was a swordsmith's greatest honor. The stronger the Hashira, the more demons they could slay, the more lives they could protect.

"Understood! Thank you, Haganezuka-san. I'll give it to him the moment he wakes up!"

The moment Tanjiro accepted the case, his arm dropped like a stone. 'So heavy! This is Kaidō-san's weapon?? How does he even swing something this massive?!'

He watched Haganezuka leave, then carried the case to the infirmary. Looking at Kaidō's still form on the bed, guilt twisted in his chest.

Tanjiro slid the wooden case under the bed, then turned toward the door. His fists clenched with determination.

'I have to get stronger. I refuse to be a burden anymore!'

—————

Inside Kaidō's Mind.

"Become a demon with me..."

"Where is the Blue Spider Lily..."

"You're the one who ruined my plans..."

"Remember—your family died because of you..."

Endless darkness surrounded him. Images flashed before Kaidō's eyes, finally freezing on three faces: his mother, his adopted sister Reika, and Retsuki.

"Muzan, stop! You bastard! AHHHHH!!" Kaidō's eyes blazed with fury. He reached out desperately, trying to save them, but the darkness was infinite, each step impossible.

As he struggled forward, Muzan materialized before him, extending his whip-like appendages. "I will not allow another person like Yoriichi Tsugikuni to interfere with my plans!"

"Muzan, don't you dare touch my family!"

"MUZAN, I'M COMING FOR YOU!" His palm shot forward, smashing Muzan to pieces—

—————

Butterfly Mansion.

BANG!

Kaidō bolted upright in bed, palm striking out. The moment consciousness returned, he realized it had all been a dream.

"It was... just a dream?"

Something felt off. He turned his head slowly.

The entire Butterfly Mansion medical staff, plus Tanjiro and the others, had gathered in his room. Every single person stared at him with wide eyes and gaping mouths—large enough to fit entire eggs.

Only Aoi had the presence of mind to react. She pointed toward the wall.

Following her finger, Kaidō spotted Zenitsu plastered against it like a pancake.

"Why... is it... always... me..." Zenitsu groaned, then slowly slid down the wall like melting cheese.

Kaidō's palm strike had sent Zenitsu flying. Fortunately, he hadn't put much force behind it, or Zenitsu would be back in a hospital bed.

"Zenitsu! My bad..." Kaidō pressed his palms together apologetically.

Kanae Kocho smiled warmly. "Kaidō-kun, you're finally awake! You've been unconscious for over two months!"

"Kaidō-san, thank god! We were so worried!" Tanjiro exclaimed.

"WAHAHA! White-Hair, you're finally up! I've been waiting to challenge you!" Inosuke bounced excitedly.

"That's right, Dragon Hashira-sama! We were all so concerned!" The three younger girls—Kiyo, Sumi, and Naho—chimed in together.

"Thank you, everyone. I'm sorry for worrying you."

"Actually, the person you should thank most is your sister Retsuki-chan," Kanae said gently, gesturing beside him. "She hasn't left your side once."

Kaidō turned. Retsuki stood there, tears streaming down her face.

"It's okay, oniichan. I'm just... I'm so happy you're awake! I thought... I thought you'd never wake up again!" Her voice cracked. "Sob... I was so scared you were gone forever!"

He pulled her into a tight embrace. "I'm sorry, Retsuki. It's my fault. I made you worry."

"Sob... I thought... I'd lost my family again... Oniichan, I was so afraid... Please don't leave me!"

"Never. I'll never leave you."

Kanae quietly gestured for everyone to leave, giving the siblings their moment.

—————

The Next Day.

The morning after waking, Kaidō began physical rehabilitation training.

The System's voice echoed in his mind for the first time in months.

[Host, you're finally awake!]

'Yeah. Thanks to that Berserk Pill you rewarded me with. Without it, I couldn't have matched Akaza in that state.'

[Everything you accomplished was through your own efforts, Host. The System merely provided tools. Also, you have an unclaimed Hidden Quest reward. Would you like to receive it?]

'Claim it!'

[Ding! Hidden Quest: Save Kyojuro Rengoku]

[Rewards: Substitute Puppet x2, Improved Clone Talisman x10, Forging Stone x1, +10% Interdimensional Energy, Queen Experience Card x1]

[Current Interdimensional Energy: 65%]

Kaidō deliberately ignored the last item. Ever since the upgrade, his System had developed a mischievous streak, occasionally rewarding him with... questionable items.

Substitute Puppet: Fuses with the body. When the host faces lethal danger, automatically dies in their place.

Improved Clone Talisman: Upgraded version of the original. Duration extended from three hours to twelve.

Forging Stone: Enhances weapons to superior quality.

'The Substitute Puppet is perfect for the Infinity Castle battle. The Forging Stone can strengthen my greatsword. And the improved Clone Talismans are excellent too. These rewards are amazing!'

His excitement was palpable. Another layer of protection for everyone's survival.

'Shame I missed two months of sign-ins while unconscious. But I can't complain—at least Rengoku survived!'

[System, use this month's Sign-In.]

[Ding! Sign-In successful!]

[Item Obtained: Jade Pendant]

[Ding! Compensating Host for missed Sign-Ins during coma: Max-Level Culinary Skills, Max-Level Handicraft]

Jade Pendant: Blocks any three attacks for the wearer.

He examined it—an exquisite lotus-shaped pendant, pure white and flawlessly crafted.

'The System's thoughtful. This jade pendant... I'll give it to Retsuki. When I'm not around, it'll protect her three times. Especially during the Infinity Castle battle...'

A sudden thought struck him. His body had experienced abnormal symptoms on the Mugen Train. He needed answers.

'System, what happened to me on the train? Why did my body react that way?'

[The Dragon Blood you consumed wasn't fully absorbed. During combat, your body accelerated absorption through physical exertion, causing the abnormalities. Combined with the Berserk Pill at the critical moment, your body overloaded and you fell into a coma.]

'So that's why I felt terrible—burning up, consciousness fading. It all makes sense now.'

Understanding the cause brought relief. With both his Mark and Transparent World active, he'd been more than capable of killing Akaza. But the Berserk Pill had pushed his body beyond control, preventing the finishing blow.

Still, the outcome was what mattered. Kyojuro survived. Nobody lost.

"Time to get back to training. Based on my timeline... about a month and a half until the Entertainment District Arc."

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

Later That Day

"Kaidō-san! Wait up!" Tanjiro called out as Kaidō passed through the courtyard.

"What's up, Tanjiro?"

"While you were unconscious, Haganezuka-san asked me to give you your Nichirin blade. It's under your bed—I forgot to mention it yesterday!"

"Oh, thanks! I appreciate it."

"Um, Kaidō-san... could I see your weapon too?"

"Sure!"

At the Infirmary—

They retrieved the massive wooden case from under the bed. Opening it revealed the reforged greatsword—identical to the original design. Kaidō lifted it, and the blade gradually shifted to blood-red.

"Still feels perfect. Haganezuka-san's craftsmanship is incredible."

"Thanks for bringing it, Tanjiro!"

"It's nothing, really!"

Tanjiro watched Kaidō leave with the blade, but couldn't bring himself to relay Haganezuka's gruff words of concern. Some things were better left unspoken.

—————

Kaidō's Estate.

Back in his room, Kaidō retrieved the Forging Stone, mentally commanding it to fuse.

A blue light enveloped the greatsword. Minutes later, the stone merged completely.

He could feel the difference immediately. The appearance remained unchanged, but it was sharper, heavier, fundamentally stronger.

'Now I don't have to worry about my weapon breaking. Looks like being unconscious let me dodge Haganezuka's wrath this time!'

"Better take a bath. Being unconscious for two months feels disgusting."

Kaidō opened the bathroom door.

He froze.

Retsuki stood completely naked beside the large wooden tub, towel in hand, mid-wipe. Her petite, delicate frame was on full display—including assets that definitely shouldn't belong to someone her size.

Time stopped.

They stared at each other.

"I'm sorry, Retsuki! I-I-I didn't mean to! I'm leaving!" He slammed the door and bolted, hand clamped over his bleeding nose.

Inside the bathroom, Retsuki collapsed onto the floor, face burning crimson down to her neck.

"This is so embarrassing... Oniichan saw everything..."

She buried her face in her hands, heart pounding like a drum.

But remembering Kaidō's flustered expression made her giggle despite herself. "Pfft~ Oniichan can be cute too sometimes!"

—————

Living Room.

Kaidō sat in a chair, head in his hands, utterly mortified.

'What do I do?? How do I apologize?? She's my little sister—why am I having these thoughts?! GET IT TOGETHER!'

"Oniichan, are you okay?"

"AHHH!!" He jumped a foot in the air.

Retsuki had appeared beside him at some point, now fully dressed.

"S-sorry, Retsuki! About earlier—I should've knocked first!"

"It's fine, oniichan. I don't mind. You didn't do it on purpose." Her face was still flushed pink.

Awkward silence descended.

"Here, Retsuki. This is for you." Kaidō broke the tension, pulling out the jade pendant.

"Wow, it's beautiful! What is it, oniichan?"

"A gift. I hope you like it. Let me put it on you."

"Thank you, oniichan!" She beamed, touching the pendant. It felt cool and smooth against her skin.

Kaidō suffered in silence, standing behind her. She was shorter than him, and having just bathed, her hair carried a floral scent that brought those images flooding back.

He shook his head violently, dispelling the thoughts.

"Retsuki, I want you to wear this always."

"I will! I promise! Thank you, oniichan—I'll treasure it forever!"

—————

Two Weeks Later.

After two weeks of rehabilitation, Kaidō had fully recovered. He met with Shinjuro Rengoku to reclaim his patrol territory.

"Haha! Kaidō, you look good as new! Come visit sometime—Senjuro and Ruka both want to see you again."

"Absolutely, Shinjuro-san. I'll stop by soon."

"Excellent! It's settled then. I need to get back to training some junior swordsmen."

Watching Shinjuro leave, Kaidō turned toward his patrol zone. That familiar, sinister smile crept across his face.

"Hehehe... demons, I hope you're ready to run. Because guess what? I'm baaaack! Kuroha, let's go! Time to hunt some demons tonight!"

His crow landed on his shoulder, waiting for nightfall.

The System observed Kaidō's expression and offered a silent prayer for the demons: three seconds of mourning.

—————

That Night. On Patrol

"♪ La la la~, la la la, I'm a demon-hunting expert! Just waiting for nightfall to catch some prey! ♪"

"♪ Walking and searching, what a lovely night~! One demon, two kidneys! ♪"

Kaidō strolled down a moonlit path, singing a modified tune. He'd already eliminated two or three demons tonight, which sparked an interesting thought.

'Demons regenerate everything, right? Even kidneys. So if I brought one back to my world... wouldn't that be infinite organ harvesting?!' His eyes gleamed with entrepreneurial excitement.

[Host, I strongly suggest you abandon this impractical idea immediately.]

'Why?!'

[Demons from this dimension would become endangered species in yours.]

'...Fine, fine. I was just thinking out loud anyway!'

Passing through a village, Kaidō spotted two demons acting suspiciously. That predatory grin returned.

"Hehe... tonight's quota just went up!"

He crept silently behind them.

"You sure that terrifying white-haired Demon Slayer left the area?" one whispered nervously.

"I'm positive! Now shut up and let's eat before we leave. I keep feeling like something's watching us..."

Just as they prepared to attack, two hands landed on their shoulders.

"Hey, don't touch me! I'm trying to concentrate here!"

"I didn't touch you!"

"Then whose hands are—"

Cold sweat poured down their faces. A horrifying realization dawned.

"Hi there, demon gentlemen~ Want to play a game? It's called 'Infinite Organ Regeneration!' Sound fun?"

The demons turned their heads mechanically. The face they saw was the last thing they wanted to see. Their legs trembled violently. They forgot how to run.

"What's wrong? Am I really that scary? I just want to play a game."

"AHHHHHH!!" Both demons fainted dead away.

"Seriously? You passed out? You're demons. Way to embarrass Muzan." Kaidō sighed, retrieving rope from his inventory. He tied them up, grabbed a leg each, and dragged them toward a nearby forest, humming cheerfully.

"♪ La la la~, la la la, I'm a demon-hunting expert... ♪"

[Poor bastards...] The System offered another three-second prayer.

From the forest came agonized screaming.

"Ahh... ohh... urk..."