Chapter 38: The Butterfly That Was Lifted Up. The True Face of Tengen Uzui

On this day, Zero finally had some rare free time—he didn’t patrol his assigned territory, and neither did the other Pill Members, all of whom had taken a short break.

As for the reason…

Naturally, it was because of what Zero and Shinobu Kocho had done.

They hadn’t just cleared all the demons in their own regions—they’d gone into other Pill Members’ territories and wiped out demons there too.

Not even ashes were left. Others couldn’t understand why these two were competing so fiercely.

Zero’s actions were understandable—he needed to gather intelligence and related information—and as for intruding into other Pill Members’ territories, they all pretended not to notice.

But for them, this wasn’t a bad thing; the free time allowed them to continue training and improving their strength.

But Shinobu Kocho… they simply couldn’t figure him out.

So they gave up and just ate, drank, trained, soaked in hot springs, and…

(??? Cough, cough, off-topic.)

Kamado Kie managed everything perfectly at Zero’s residence—she cleaned the house spotless and took on the duties of a nanny.

Zero told her not to work so hard, but she replied that compared to what he did, her tasks meant nothing.

As for Takeo and Shigeru, they shared household chores; Hanako cared for Rokuta.

But every time Rokuta saw Zero, he wanted to be hugged.

After soothing Rokuta to sleep, Zero handed him over to Hanako.

Not knowing what else to do, he went straight to the courtyard to organize and maintain all the equipment in his [Nanospace].

If left unattended for too long, equipment performance would degrade.

In the courtyard, Zero first took out his scythe and wiped it down, checking for damage—only to find it unchanged, as good as new.

Then he retrieved the [Dark Alloy Model IV], the [Dark Alloy Annihilation Sniper Cannon], the [Quantum Dual Pistols], and other weapons, activated his [Analytical Glasses], scanned each item one by one, disassembled them, and inspected every component…

After finishing, he reassembled all weapons and returned them to the [Nanospace], then took out the motorcycle, armored vehicle, and [Dark Alloy Battle Armor] to scan and inspect them…

After several hours, he had checked most of the weapons—but something still felt missing.

He glanced at the [Nanospace] and realized the [Giant Dark Alloy Battle Mech] had never been inspected.

Although he’d never used it since arriving in this world.

To prevent any potential problems—if he ever needed it in a dire situation—he should check it once.

He immediately retrieved the [Giant Dark Alloy Battle Mech].

Hum!

A ripple surged through the air, and a massive mech composed of dark red and black descended from the sky.

With a thunderous “Boom,” it landed solidly in the courtyard.

“Gaaah!” The kaiju on the tree, Snow, was startled into immediate flight, nearly losing balance and crashing into the wall.

Looking at the ten-meter-tall battle mech, Zero wondered—if the idiotic Muzan Kibutsuji saw this, would he flee in terror?

Unfortunately, the battle mech had drawbacks: though its defense and destructive power were formidable, its agility was sluggish, and it consumed vast amounts of [Energy Crystals].

If agility were rated from 1 to 10, this mech could only reach about 8.

But these weren’t the main issues—at least self-defense was no problem.

“Zero-nii, what happened…!?” Hanako, holding the startled Rokuta, stood at the window, her mouth gaping at the strange iron monster.

Kamado Kie and the others stepped out of the house, about to ask what was going on—then froze, their expressions identical to Hanako’s.

Kamado Kie covered her mouth with both hands; Takeo and Shigeru stared in utter shock.

“Master, what are you doing…?” Xiao Yue flew over and landed on Zero’s shoulder, confused why he’d retrieved the mech.

“Sorry, Auntie Kie—this is something I built. I haven’t used it in a long time, so I took it out for inspection. I’m sorry I scared you.”

Hearing Zero’s explanation, Kamado Kie finally regained her composure. “Oh… you scared me half to death—I thought something terrible had happened.”

She patted her chest, relieved.

Takeo and Shigeru stared at the giant mech, unable to resist touching it, peering left and right, growing more fascinated by the second.

Takeo: “Zero-nii, what is this? It looks incredibly powerful!”

Shigeru: “Yeah, it’s amazing! I’ve never seen such a huge piece of iron!”

Zero: “This is a mech I built long ago. Since I had time today, I took it out for inspection.”

“Zero-nii, you’re so amazing!” Takeo and Shigeru gazed at Zero with pure admiration.

“Alright, alright—Takeo, Shigeru, come inside and help me cook. It’s almost noon!”

“Okay~” x2

Hearing their mother’s call, Takeo and Shigeru reluctantly left—but inside, they dreamed of sitting atop that mech.

Zero waved at Hanako and Rokuta at the second-floor window; they waved back.

Then he turned—and nearly jumped out of his skin.

“Huh?! What’s going on?! Why are you all here?!”

…

Boom!

The sound echoed through the Demon Slayer Corps headquarters. Most assumed a demon attack—but it was daytime, so that seemed impossible.

Ubuyashiki Kagaya immediately ordered someone to investigate the source of the noise.

As he stepped outside, he saw a towering black-and-red monster standing near Zero’s residence. Worried for Zero, he prepared to go with the group.

“Amitabha, Lord Ubuyashiki, please remain here—we’ll go investigate!”

“Yes, Lord Ubuyashiki, we’ll handle it!”…

The Pill Members all urged him to stay. Ubuyashiki, unable to refuse, relented: “Fine—but be careful. I don’t want to lose any of you.”

“Yes!” x11

The ten Pill Members, along with the former Flame Pill, rushed toward Zero’s residence. Butterflies Shinobu was the most anxious, fearing something had happened to Zero.

But when they saw the black-and-red iron monster, every single one sucked in a sharp breath.

Gyomei Himejima couldn’t see it—but he felt it.

Hssss!

The mech stood motionless, yet radiated an invisible aura of lethal intent.

This mech had accompanied Zero through countless battles, slaying over ten thousand mutated beasts, and had absorbed much of the battlefield’s killing aura.

Only Shinobu stood at the back, able to see only the upper half of the mech—its lower body was hidden. She had no idea what it looked like.

The others were taller and crowded around it; she was too short to see over them.

Tomioka Giyuu reached out, grabbed Shinobu by the back of her neck, and lifted her up like a kitten…

Shinobu: (ー`?′ー)!!!

Tomioka Giyuu: You’re welcome.

“Huh?! What’s going on?! Why are you all here?” Zero turned and saw everyone gathered—startled, he asked.

Shinobu Kocho: “It’s because of you, you idiot!”

Rengoku Kyojuro: “Zero, are you alright? What is this?”

Uzui Tengen: “This is magnificent! Zero, what is this gorgeous iron monster?! I’ve never seen anything so magnificent! So gorgeous!”

Shinobu Muichiro: “What’s this thing again?”

…

After much explanation, they finally understood—and marveled at how Zero’s mind worked to create something like this!

Though they didn’t understand how he built it, that didn’t stop their admiration.

Eventually, everyone dispersed—except Tomioka Giyuu, who was foaming at the mouth and turning purple, carried back by Uzui Tengen and Rengoku Kyojuro. As for why…

Shinobu: “Tomioka Giyuu seems to have eaten something spoiled. Take him to Butterfly House—I’ll check on him.”

Everyone knew Shinobu had done something—but only she knew what.

After all the commotion, Zero completed his inspection of the [Giant Dark Alloy Battle Mech]. As he prepared to return it to the [Nanospace], another thought struck him.

To prevent any unforeseen issues, he took out two hundred [Energy Crystals], infused them into the mech’s core, and stored them—then returned it to the [Nanospace].

He thought again, and infused [Energy Crystals] into all his other weapons too—not for any reason, just to be cautious.

After all, better safe than sorry.

Having finished, Zero relaxed and took out his diary to write.

【X Month X Day, Daytime, Weather: Heaven Watching a Show】

【Another leisurely day—the demons in my territory have started slacking off again…】

………

Time slipped away, swift as wind.

In the blink of an eye, half a year had passed.

After patrolling his territory, Zero traveled to Higurashi Mountain—he’d promised Kamado Kie and the others he’d visit Tanjiro and Nezuko if he had time.

When he arrived at Higurashi Mountain, he followed the kaiju’s directions into the forest.

After some time, he reached the mid-slope and saw a small wooden cabin ahead on the forest path.

Just as he prepared to advance, he sensed movement nearby!

It was his long-honed combat instinct—he felt someone hiding nearby, preparing to strike—but there was no killing intent.

Zero merely smiled, gripped his scythe tightly, and carefully sensed every whisper of wind and rustle of leaves.

Shhh!

In that instant, a flat slash erupted from his right rear side, hurtling straight toward him.

Water Breathing. First Form. Surface Slash!

Kō!

With a spin, the scythe and Nichirin Blade collided, sparking and dissipating the flat slash.

Immediately twisting the scythe, he deflected the Nichirin Blade! The blade’s edge pressed into the ground, lifting his body into the air as he kicked forward.

Water Breathing. Third Form. Flowing Dance!

The attacker reacted in turn—just as Zero’s kick neared, he vanished into a phantom image, creating distance between them.

Zero had only seen the attacker as a man wearing a red tengu mask; by his posture, he seemed elderly.

But there was no astonishment—on the instant his body landed, he turned defense into offense, powering his leg to push off and swung the scythe again in pursuit.

Gripping the scythe’s handle at its tail end, he extended his reach and delivered a powerful horizontal sweep.

Water Breathing. Second Form. Water Wheel!

The tengu-masked elder did not panic—he leapt upward, dodging the sweeping scythe, and as he descended midair, attacked Zero’s back.

Yet all of this seemed within Zero’s anticipation—he bent forward to evade, planted one hand on the ground to brace himself, and kicked again.

This time, he intended to shatter the mask—to see who lay beneath.

The tengu-masked elder shifted one step sideways, dodging the flying kick.

He launched another attack immediately.

Water Breathing. Fourth Form. Crushing Tide!

This attack came like a tide—multiple rapid strikes cascaded upon Zero.

In that instant, Zero rose, gripping the scythe handle and spinning rapidly around himself, deflecting every strike.

Once the assault ended, he charged forward again, scythe in hand.

His movements flowed seamlessly.

Water Breathing. Seventh Form. Dew Ripple Thrust!

A straight-line strike shot forth—its speed and angle rippled like ripples on water, astonishingly swift.

Seeing it, Zero raised his scythe horizontally before him—the thrust pierced directly through the handle.

Sssshh!

The Nichirin Blade’s edge scraped against the scythe’s handle, sparking, then continued its thrust forward.

Zero arched his body backward to evade, then twisted, rotating the scythe to press against the Nichirin Blade, forcing it down to the ground with a firm push.

In that same instant, he leapt upward, appearing behind the tengu-masked elder, gripping the scythe’s tail end at a distance, its blade pressed against the man’s throat.

“You’ve lost.”

Hearing the voice behind him, the tengu-masked elder was stunned.

He had not expected this hooded figure to possess such combat experience—no breathing technique, yet he had mastered the fight purely through skill, forcing the elder into disadvantage.

Feeling the biting cold of the scythe’s edge, recalling the battle, it all felt unreal—yet it had truly happened before his eyes.

“Zero… sir, correct? My name is Rinjū Saigōji. I am the Water Breathing instructor.” Rinjū Saigōji spoke as he sheathed his Nichirin Blade.

Former Water Pillar—Rinjū Saigōji

Had his nose not been sharp enough to detect Zero was male, and had Tōgō Yūji not written to confirm it,

he might have mistaken Zero for a girl, based solely on appearance.

Zero sheathed his scythe and said, “Call me Zero. Apologies for the abruptness—I came to visit Tanjiro and Nezuko. My earlier actions were impolite.”

Rinjū Saigōji turned and said, “Old man merely grew curious—wanted to see what manner of man could slay Upper Moon demons, face Kokushibō, and drive him back.”

Zero: “You flatter me.”

Rinjū Saigōji: “Come inside. Tanjiro is training atop the mountain. Nezuko is well—though she remains asleep.”

Zero: “Very well. Thank you for the intrusion.”

Soon after, Zero followed Rinjū Saigōji into the house, removed his shoes, and sat cross-legged.

“How is Yūji now?”

“He is well. Still struggles to communicate with others.”

“I see… Yūji was raised under my watch since childhood—always quiet. Sigh… Nezuko is in that room. Go see her. I’ll prepare dinner.”

“Thank you.”

Rinjū Saigōji rose and left alone. Zero entered another room, slid open the wooden door, stepped inside, and closed it.

Seeing Nezuko asleep in bed, nibbling her mouthguard, Zero smiled faintly, recalling their first meeting.

He sat beside Nezuko, gently lifted her head onto his lap, offering her his knee as a pillow once more.

He softly pinched her soft, bouncy cheek.

“You sleep so much, Nezuko. Is this how you recover your strength?”

From the moment he met Tanjiro’s family, memories flashed through his mind like scenes from a scroll.

Every event, every memory, felt as if it had happened yesterday.

Nezuko’s steady breathing, her peaceful face—she looked like a sleeping beauty.

Meanwhile, he reviewed the information on Rinjū Saigōji.

【Name: Rinjū Saigōji—male】

【Age: 70】

【Identity: Demon Slayer Corps Instructor】

【Rank: Former Water Pillar (retired)】

【Breathing Style: Water Breathing】

【Disciples: Sanemi (deceased), Shinobu (deceased), Tōgō Yūji, Kamado Tanjiro (training), …】

【Special Ability: Sense of Smell】

【Brief: Former Water Pillar of the Demon Slayer Corps. After retiring from frontline duty, he resides alone on Sōkiri Mountain. As an instructor, he nurtures the next generation and is deeply revered by his disciples.】

【He wears the fearsome tengu mask because, in the past, demons mocked his gentle face.】

【Possesses a unique, acute sense of smell—he can discern human emotions by scent and identify demons disguised as humans.】

【Note: In his youth, Rinjū Saigōji’s overly gentle appearance was mocked by demons. The former Thunder Pillar advised him to wear a mask to conceal his face.】

“Former Thunder Pillar… There must be a story there. Hmm… what does Rinjū Saigōji’s face look like beneath that tengu mask?” Zero wondered curiously…

“Sanemi… Shinobu… excluding Tōgō Yūji and Tanjiro, twelve others have died in total… Something must have happened.”

Outside, night had fallen.

Not long after, Tanjiro’s voice came from outside the door: “Master Rinjū, I’m back.”

Seeing the room empty, Tanjiro assumed his master had stepped out.

He slid open the door to check if Nezuko had awakened—and saw Zero, kneeling, offering her his knee as a pillow.

“Zero-nii?!” Tanjiro exclaimed, delighted and surprised—he hadn’t expected Zero to be here.

“Long time no see, Tanjiro! I came to visit you and your sister. How are you getting on here?”

“Yes, Zero-nii. I’m doing well. Master Rinjū has been teaching me.”

“Is that so? Here—this is for you.” Zero pulled a letter from his chest—the one Kamado Kujira had entrusted him to deliver.

Tanjiro took the letter, opened it, and found messages of comfort and care from his mother and younger siblings.

Reading each word, each sentence, Tanjiro nearly wept.

“Thank you, Zero-nii!”

“You’re welcome. If you’d like to write back to your family, I can carry it for you.”

“Really?! Then please, Zero-nii! I’ll go wash up first, then write.”

Saying this, Tanjiro rose to bathe—he was covered in mud and sweat from a full day of training.

Splash!

Soon after Tanjiro left, Rinjū Saigōji opened the wooden door, entering with several freshly cleaned fish in hand.

Zero gently laid Nezuko down, tucked her in, and stepped out of the room.

Watching Rinjū Saigōji simmering fish soup, Zero sat across from him, silent, and helped add firewood beneath the pot.

“You’re curious why I always wear this mask?” Rinjū Saigōji asked—he had smelled Zero’s curiosity.

“Yes. But it’s your personal privacy—I won’t pry, no matter how curious I am.” Zero admitted openly.

“I see…” Rinjū Saigōji seemed lost in thought, yet never paused stirring the soup.

Half an hour later.

Tanjiro had finished bathing, changed into clean clothes, and the fish soup was ready.

The pot held a milky-white broth, fragrant and steaming.

Tanjiro brought three bowls, ladling fish and broth for Rinjū Saigōji, then for Zero and himself.

Zero: “Thank you.”

Tanjiro: “Thank you, Master Rinjū! I’ll dig in!”

Rinjū Saigōji then took a small bowl, filled it with fish meat, and placed it before the kurogami, Snow.

Kurogami Snow: “Thank you, Water Pillar.”

Tanjiro: (*???)!! U-U-U… the crow just spoke!

Zero: “Tanjiro, don’t be startled. When you become a Demon Slayer, you’ll have your own kurogami too.”

Tanjiro: “Yes, Zero-nii. I understand.”

Even while eating, Rinjū Saigōji lifted his mask only slightly—exposing only his mouth.

But this time, he removed his mask, revealing his true face.

Tanjiro Kamado’s true face

It was a face lined with faint wrinkles, appearing kind and gentle, yet marked by weariness—clearly shaped by many trials.

Zero now understood why he had done this; likely because of his own curiosity…

Beside him, Tanjiro froze again—he had never seen Tanjiro Kamado’s face without the mask before; it was soft, gentle, and warm.

“Eat. It won’t taste good if it gets cold.”

Thus, the three and a crow enjoyed tender fish and savory fish broth, spending the night there.

…

Midnight.

Zero couldn’t sleep, unsure what to do next, so he walked alone to the mountaintop, feeling the mist and night wind.

As he walked, he reached a graveyard where twelve tombstones stood.

Looking at the names on them, Zero understood these were Tanjiro Kamado’s deceased disciples; though he didn’t know the full story, he guessed at least part of it.

These children must have died during the Mount Fujikawa trials before he joined the Demon Slayer Corps.

After gazing for a while, he turned to leave—when suddenly, he felt two eyes watching him from behind the trees.

He turned back, but saw nothing. Yet he had definitely felt them.

【Scan activated】

【Scanning… no anomalies detected】

“An illusion?…”

After Zero descended the mountain, two “people” stepped out from behind the trees—a boy and a girl.

Shinobu, Mitsuri

The man was a youth with medium-length flesh-colored hair, silver eyes marked with horizontal stripes, and a long scar extending from the corner of his mouth to his cheek. He wore a demon-slaying fox mask with a scarred mouth and a feathered cloak woven in yellow, orange, and green tortoiseshell pattern.

The woman was a mysterious girl with medium-length ink-green hair, wearing a fox mask adorned with a flower pattern on the cheeks.

“Incredible perception!”

“Yes. Just one glance and he sensed us.”

“Clearly, his strength is formidable.”

“Shouldn’t we meet him?”

“Let’s wait for another chance. That thing inside Mount Fujikawa has been unusually agitated lately…”

“Hmm… should we meet Tanjiro tomorrow?”

“Not yet…”

“I understand.”

…………