Mugen Train

The morning air at the Butterfly Mansion carried the distinctive bitter scent of medicinal herbs.

The Sapphire Star had just stepped into the courtyard when she saw Tanjiro Kamado ready to leave, his wooden backpack strapped on.

Beside him, Zenitsu nervously checked his Nichirin Blade's scabbard, muttering something too indistinct to make out.

Inosuke Hashibira was slapping his Boar Headgear with loud smacks, apparently performing some strange ritual with it...

"Hey, buddy! Packing up? Heading somewhere far?" The Sapphire Star was rather surprised. The trio had only recovered a few days ago, and they were already going on another mission.

"Ah, Lady Sapphire Star!"

Tanjiro immediately turned at her voice. His face showed the fatigue of training, but his crimson eyes shone unusually bright. His breathing was long and steady, each breath seeming to stir the air around him ever so slightly.

Oh-ho, not bad~

The Sapphire Star could clearly sense that Tanjiro's breathing had become steadier and better suited to combat. This boy was growing even faster than she had expected. If she ever got the chance to bring him back home, he would surely make a fine Long Sword user!

"Yes! We've received new orders to board a train and rendezvous with the Flame Hashira!"

Tanjiro straightened his back, his voice brimming with determination:

"And... I've mastered Total Concentration: Constant! I'm still not very good at it, but I'll keep working hard! I won't let you down!"

He could sense the deep, formidable presence emanating from the Sapphire Star, like an ancient iceberg. It only strengthened his determination to pursue greater power.

"Constant? Oh, that trick where you keep your Breathing Style active all the time?" The Sapphire Star nodded.

"Nice work, kid! Once you've mastered it, you can fight twice as long! No need to chug Dash Juice every five minutes like certain dual-blade users. Anyone who didn't know better would think they had kidney problems at their age... Come on, I've got a present for you!" The Sapphire Star took out a necklace and handed it to Tanjiro.

"What's this?" Tanjiro accepted the necklace. Its exquisite craftsmanship was beyond anything this era could produce, and its scent didn't belong to this world.

"Miss Sapphire Star, isn't this too valuable?" Tanjiro asked worriedly.

She gave his shoulder a hefty pat, but his footing was solid, and he barely swayed.

"What the hell are you being so polite for? Take it! Make sure you stay safe. Stay alive and get stronger, so you can protect your sister and everything else you want to protect! Now go chop whatever demon crap is on that train into little pieces!"

"Yes! Thank you!" Tanjiro nodded firmly and put the necklace away, then prepared to turn and leave. The Sapphire Star's blunt encouragement always carried a reassuring strength.

Just then, as though she had remembered something, the Sapphire Star hurriedly called out:

"Wait, no, I almost forgot the important part! Don't go yet. Come back! Catch!"

The Sapphire Star quickly pulled out a heavy, irregularly shaped object and casually tossed it to Tanjiro.

Tanjiro caught it instinctively. It felt cold and heavy in his hands, with no unusual scent.

"Wh-what is this?" Tanjiro had a vague, ominous feeling.

"Nothing much. I happened to cut down a Lower Rank demon earlier. Used a little trick, so the head's still pretty intact. Oyakata-sama told me to give it to you. No idea whether you want to kick it around or feed it to your sister, but anyway, it's yours too!"

"A Lower Rank demon's head?! For... for me?!" Tanjiro's pupils contracted sharply, and he nearly threw the thing away.

He stared at the Sapphire Star in disbelief:

"Lady Sapphire Star! Why would you give me something so dangerous? This... this should be handled by the Kakushi or the Hashira! And my sister doesn't eat demons!"

He simply couldn't understand why a demon's head, especially one belonging to the Twelve Kizuki, would be entrusted to a newly recruited swordsman like him.

The Sapphire Star shrugged, her expression saying, "Don't ask me."

"Beats me. Oyakata-sama's idea. That's what he said."

Then the Sapphire Star cleared her throat twice and imitated Ubuyashiki's voice:

"Give it to Tanjiro. It may be of great use to him... Anyway, I've delivered it. Won't keep you any longer. I'm off~"

"The Master's wishes..." Tanjiro murmured, looking at the cold bundle.

Miss Tamayo's gentle, sorrowful face instantly flashed through his mind, along with Yushiro's wary gaze.

Could the Master... know about Miss Tamayo?! Is this for her research?

The Master had tacitly approved, even supported, his contact with Miss Tamayo and provided such a precious "sample."

An immense sense of trust and responsibility settled over Tanjiro's heart.

"Chachamaru!" Tanjiro called softly toward his collar.

"Mew-mew!"

A faint reply sounded, and a small cat silently appeared in the shadows beneath the eaves.

"Sorry for the trouble." Tanjiro secured the bundle and gently handed it to Chachamaru.

"Please deliver this safely to Lady Tamayo. It's extremely important!"

Chachamaru sniffed the bundle, struggled to wrap tiny paws around the package that was far too large, and gave Tanjiro a resolute little nod.

"Mew!" With another soft cry, Chachamaru became a blurry white streak and vanished silently into a corner of the Butterfly Mansion's courtyard, carrying the heavy head on a vital secret mission.

Tanjiro watched Chachamaru disappear and let out a long breath. When he turned back to the Sapphire Star, his eyes held a complicated emotion he couldn't put into words:

"Lady Sapphire Star, thank you! And... please thank the Master for me!"

"All right, it's nothing. Aren't you catching a train? Quit dawdling and get going. Trains don't wait!"

"Yes!" Tanjiro, Zenitsu, and Inosuke answered together. The three shouldered their bags, took one last look at the Butterfly Mansion, and hurried toward the station.

The Sapphire Star watched the three boys disappear down the road, rubbed her chin, and muttered:

"Come to think of it, what use does that kid have for a Lower Rank's head? I honestly thought Nezuko could eat it, evolve into some super form, and punch Muzan's damn head off or something. Why'd he give it to a kitty...? Whatever. Oyakata-sama said to give it to him, so I did."

She pictured Nezuko sprouting a body full of bulging muscles, yelling "Atatatatatata!" and declaring, "You are already dead..."

Honestly, she couldn't figure out why Oyakata-sama wanted Tanjiro to have the Lower Rank's head. Nor did she know why she had suddenly wanted to give Tanjiro a present. A powerful intuition had simply told the Sapphire Star that he really needed it.

She shook her head. All that thinking had made her hungry.

So she turned and strolled toward the Butterfly Mansion's dining hall, calculating how many bowls of rice she should put away today.

The Butterfly Mansion's food was different from headquarters'. It tasted fresher and whetted the appetite. After eating so many meals at headquarters, having a couple here felt downright amazing.

Time passed quickly.

"Delicious! Delicious!"

The moment the trio boarded the train, they heard a booming, spirited voice.

"Mr. Rengoku!" Tanjiro hurriedly bowed. "I'm Tanjiro Kamado! It's a pleasure to meet you!"

"Mm! Such enthusiasm!" Kyojuro Rengoku nodded in satisfaction.

The carriage was dimly lit, its air stuffy. Most of the weary passengers were curled up in their seats, drowsy, while only a handful still spoke in hushed voices.

Without warning, an indescribable wave of sleepiness surged over them all!

Their eyelids grew heavy as lead, their limbs lost all strength, and even their breathing became weak and sluggish...

"Ne... zu... ko..." Zenitsu's slurred mumbling sounded nearby.

"...Snore..."

Atop the Mugen Train, Lower Rank One, Enmu, enjoyed the cool evening breeze blowing against his face.

"Take this, swordsmen... A Blood Demon Art with a twenty-meter radius... This is my final Blood Demon Art..."

Ever since the other three Lower Ranks had been slain, Enmu had clearly sensed that lord's patience with him running out as well. If he couldn't produce satisfying results soon, the last Lower Rank might go out of production too...

He hadn't arranged for humans to destroy the swordsmen's spiritual cores. Once the four swordsmen boarded, Enmu had clearly sensed Kyojuro's extraordinary presence.

A Hashira, and a powerful one at that.

He had to keep all four of them asleep, then slowly digest them.

He had to use his strongest hypnosis. Fighting four awake swordsmen at once would be no different from throwing his life away.

Five Lower Ranks had died in such a short span of time. Something unusual was clearly happening within the Demon Slayer Corps. He couldn't afford to underestimate them anymore.

He had to be careful, careful, and even more careful!

He would use the most underhanded methods possible, so long as he could keep devouring powerful lives. Enmu now had only one path to survival-

Surpass that brother and sister in the Entertainment District and leap into the Upper Ranks.

One delicious Hashira would be an excellent start. If he could devour another seven or eight, perhaps he would have a chance in a rank replacement blood battle against those siblings...

At that thought, Enmu couldn't help humming softly.

Suddenly, killing intent rose from beneath his feet. Enmu hastily leaped backward.

"Holy shit!" Enmu swore, losing his composure.

"Water Breathing, Second Form: Water Wheel!"

A slash tore through the roof beneath his feet. Had he retreated a moment later, both his legs would surely have been gone.

Tanjiro drew his blade and charged onto the roof. Moonlight illuminated Lower Rank One Enmu's twisted face-

Black hair tipped with rose pink, and eerie yellow squares embedded in his cheeks.

"No, seriously, man? Tell me how you woke up! Wasn't a sweet dream of reuniting with your family good enough?"

He'd seen a ghost-no, wait, a swordsman.

He had even overdrawn his strength to unleash his strongest Blood Demon Art: Forced Slumber.

In theory, even an elephant struck by it would sleep for nearly half a year.

How had this swordsman woken up just as he came out for some fresh air? Was he cheating???

"Boar rush!"

"Thunder Breathing, First Form: Thunderclap and Flash!"

Two more voices rang out, accompanied by flying Sword Aura.

Enmu bent his body, but several attacks still struck him, sending him staggering back a few steps.

"What?? Are all of you cheating? How are you all awake?" Enmu's eyes bulged.

Was his Blood Demon Art counterfeit or something?

Every one of them was full of energy. None of them looked affected at all!

Oh, wait, that blond swordsman really was asleep. He even had a snot bubble...

Wasn't that even more of a cheat?! What did he mean, attacking in his sleep? Had someone logged into his account to play for him?

"I knew there was a powerful stench on this train. So it was you! Water Breathing, Fourth Form: Striking Tide!"

"No, no! Stop, stop!! Can you please tell me how you woke up?" Enmu asked in bewilderment as he desperately dodged the three swordsmen's attacks.

He had been careful, then more careful, cautious to a ridiculous degree. Why had he still failed? He simply couldn't understand.

"It's all thanks to Lady Sapphire Star's gift..." The necklace around Tanjiro's neck glittered.

The Sleep Resistance Charm-the ideal equipment for dealing with monsters that played dirty, such as Somnacanth and Hypnocatrice.

Hypnosis tricks like Enmu's had already been done to death back in the Sapphire Star's homeland.

Even the Sapphire Star's own attacks could carry a sleep attribute, knocking enemies straight into slumber after a barrage of critical hits.

Perhaps thanks to the outrageous luck of the Sapphire Star who guided the way, the Sleep Resistance Charm had now reached the person who needed it most.

Back on the train, Tanjiro had been eating the boxed meal the Flame Hashira had handed him.

He had to admit, it was delicious. The pork cutlet was wonderfully crisp, and the sauce tasted great too...

Something's wrong!

Tanjiro and the Flame Hashira suddenly noticed that the few passengers who had been talking just moments ago were now asleep, along with everyone else.

Everyone except Inosuke and Kyojuro, who sat around Tanjiro-Zenitsu had urgently needed the toilet and was now asleep outside its door.

Tanjiro felt warmth against his body. When he pulled out the necklace the Sapphire Star had given him, he saw it glowing.

"The enemy has already attacked! Young Kamado! It seems your necklace is the reason we haven't fallen asleep!" The Flame Hashira warily drew his Nichirin Blade.

"It... it's the necklace Lady Sapphire Star gave me... I don't know why we're unaffected either." Tanjiro also drew his Nichirin Blade, preparing for the demon's attack.

"Young Kamado! Boar-headed boy! Maintain your Breathing Styles. Don't let the Blood Demon Art overcome you. Keep Miss Sapphire Star's necklace on you. I don't need it." The Flame Hashira severed several tentacles hidden inside the carriage with a single slash.

"Such a powerful demonic presence, and I didn't notice it! I was far too careless!"

The trio had already joined forces to sever Enmu's head, which let out a rattling, mocking laugh:

"It's useless! This train is already my body! All two hundred passengers are food!"

"Hinokami Kagura: Blue Heaven!" The Nichirin Blade swept up a scorching vortex!

"Aaaaargh!!!" Enmu felt as though someone had ripped his kidneys right out. That Hashira had acted, severing the passenger carriages and separating them from his main body.

No, seriously, was it really fair for all of them to bully one frail little Lower Rank One like this?

Four against one-oh, wait, there was also a demon girl attacking the carriage's tentacles.

The total was five against one. He did not have the advantage...

"Boar rush!" Inosuke's spatial awareness surged beneath his Boar Headgear. His twin blades split the junction between the carriages. "Coward! The demon's neck is where they burn coal at the front!"

Tanjiro plunged into the coal-dust-filled locomotive. Foul-smelling flesh had already covered its machinery.

Beneath the floor, a pale section of spine covered in nerves and blood vessels throbbed-Enmu's true body.

"Not a chance!" Dozens of blood-red eyes suddenly split open along the fleshy walls! Hypnotic gazes surged toward them like a tide.

"Duck!" Inosuke fearlessly smashed his Boar Headgear into the cluster of eyes. "You don't get to see my eyes!"

Tanjiro seized the opening, driving his gleaming blade through-

Crack!

The sharp snap of the severed spine tore through the night sky! The entire train rolled and writhed like a dying giant serpent!

"Flame Breathing, Fourth Form: Blooming Flame Undulation!" Kyojuro Rengoku's roar resounded through the heavens! A tornado of flame swept through the rear five carriages, burning the proliferating demon flesh to ash.

Before the smoke and dust settled, Tanjiro struggled to his feet.

Under the moonlight, Mr. Rengoku stood leaning on his blade. His haori was tattered, but his back remained straight as a pine.

"Well done... young Kamado! Boar-headed boy! Yellow-haired boy!" He panted, but his golden, flame-bright eyes remained fixed on the figure that had suddenly appeared on the tracks...