Chapter 4: Encountering Upper Moon Two. Battle Against Dōma. Save Butterfly Kanae

“Respected my lord, please rest here tonight; should you need anything, feel free to call on me.” said Kujō Matsui.

Zero: “Alright, thank you!”

Afterwards, Kujō Matsui closed the door, not disturbing Zero and Xiao Yue’s rest.

Inside the house.

Zero lay under the covers, while Xiao Yue lay sprawled across his chest, propping her chin with both hands, her legs twitching constantly.

“Master, will you join this so-called Demon Slayer Corps?”

“We’ll see how things develop. Besides, I have a feeling this isn’t as simple as it seems. Either way, I’ll assess the situation when the time comes.”

“If possible, joining might not be a bad thing—we could gather more intelligence about this world and perhaps find a way back.”

“Mm, Master, Xiao Yue will always stay with you.”

“Thank you, Xiao Yue. Get some rest.” Zero reached out and stroked Xiao Yue’s head.

“Goodnight, Master!”

“Goodnight.”

……

Demon Slayer Corps Headquarters.

Butterfly Kanae and Butterfly Shinobu spent the entire night returning to the Demon Slayer Corps headquarters to report to the Lord, detailing everything they had encountered.

“Is that so? A white-haired boy, without learning any Breathing Technique, slew two Lower Moon demons—and carries many mysterious weapons!”

“Yes, my lord. If he is willing to join the Demon Slayer Corps, he would undoubtedly be a powerful swordsman for us.”

“What is the name of this white-haired boy?”

“His name is Zero. He has a younger sister named Xiao Yue—a remarkably strange little doll who can speak and is also very powerful.” Butterfly Kanae replied.

“I see. Then, Kanae, I entrust this matter to you. If he is willing to join, that is best. If not, do not force him. If possible, I would like to meet him—this white-haired boy who slew Lower Moon demons. I am curious to know what manner of man he is.”

“Yes, my lord.”

……

After resting one night, Zero departed from Kujō Matsui, the head of the Wisteria Pattern House, and arrived at a village.

But strangely, the villagers seemed to rarely leave their homes; even when they did, only a few appeared.

“Strange. Logically, this village should have at least eighty or ninety people—why are so few out? It’s daytime, yet something feels off.”

“Master, shall we wait until nightfall to investigate? Perhaps we’ll find our answers after dark.”

“That’s the only option. My intuition tells me something major will happen in this village tonight!”

“Don’t worry, Master—you still have Xiao Yue! Even if something big happens, Xiao Yue will help you handle it.” Xiao Yue sat on Zero’s shoulder.

“You, you little thing—thank you, Xiao Yue.”

“Mm-hmm!”

……

After informing the Lord, Butterfly Kanae spent the next day traveling to the Wisteria Pattern House, only to be told by Kujō Matsui that Zero had left a day earlier. Just as she was about to ask where he had gone, a messenger crow flew in, reporting a demon sighted in the northwest-north direction.

The so-called messenger crows were ravens bred by the Ubuyashiki clan to relay messages between Demon Slayers and the Corps headquarters.

Northwest-north was precisely the region under Butterfly Kanae’s jurisdiction. Upon hearing the crow’s report, she abandoned her search for Zero for now—slaying the demon was paramount, to prevent others from being harmed.

Yet Butterfly Kanae did not know that this demon she encountered would bring her to the brink of death.

……

Night fell.

Zero and Xiao Yue had investigated the village for three days and discovered that recently, young girls had been vanishing—especially beautiful, youthful ones. The cause: followers of the Bliss Sect.

The Bliss Sect claimed to have received divine will to redeem suffering souls. They were apostles of the Divine Child, whose leader was the Divine Child himself—said to hear the voice of God.

“Redemption? Divine Child? Hah! These self-proclaimed servants of God are fascinating! I’d like to see just what this ‘Divine Child’ is all about! Xiao Yue, let’s go investigate this so-called Bliss Sect.”

“Yes, Master.”

As Zero and Xiao Yue moved, they suddenly felt the atmosphere grow increasingly unnatural—the air carried a faint chill.

“Master, something’s wrong around here.”

“I feel it too, Xiao Yue. Scan it. Find out what’s happening.”

“Understood. Scanning… scan complete.”

“Master, there’s been a battle at the village’s perimeter—someone is fighting a demon! And this chill in the air is the demon’s Blood Demon Art.”

“Blood Demon Art?! It’s causing chill even here—this demon must be powerful! Let’s hurry over.”

“Yes, Master.”

Zero and Xiao Yue rushed to the village’s edge and found a girl fighting a demon. The girl was someone they both recognized: Butterfly Kanae.

The demon had white hair like birch bark, seven-colored eyes, and a face smeared with blood, eternally smiling with blissful indifference.

Seeing Butterfly Kanae in dire straits, Zero immediately retrieved the Nano-Alloy Annihilation Cannon Sniper from his nanospace and fired a shot at the demon.

“Boom!”

A deafening cannon blast fired a round of Annihilation Sniper ammunition toward the demon.

The demon sensed the immense threat approaching and instantly raised his iron fan to block it.

Unexpectedly, the bullet exploded, shattering the fan in his hand, injuring half his skull, and the shockwave forced him back several meters.

Seeing this, Zero rushed to Butterfly Kanae’s side and used his Analysis Glasses to scan the demon’s data.

【Analysis complete.】

【Name: Dōma (Ice Demon)】

【Rank: Upper Moon Two】

【Other Identity: Leader of the Bliss Sect.】

【Superior: Demon King—Muzan Kibutsuji】

【Age: 200 years】

【Weapon: Iron Fan】

【Blood Demon Arts: Lotus Ice, Vining Lotus Blossom, Withered Garden’s Snowfall, Frozen Cloud, Frosty White Princess, Abyssal Winter Pillar, Crystal Child, Mist Ice: Lotus Bodhisattva.】

【Caution: Dōma’s ice mist carries ice poison. Inhaling it damages alveoli and causes death. Skin contact slows movement.】

【Recommendation: Use long-range weapons, or employ weapons infused with energy crystals to generate burning effects for decapitation. Always beware Dōma’s ice-poison attacks.】

Zero spent three seconds reading the Analysis Glasses’ data, then looked at the fallen Butterfly Kanae—the status read: 【Severely injured, alveoli damaged, near death.】

He immediately retrieved a Quantum Shield from his nanospace, infused it with an energy crystal, and placed it over Butterfly Kanae’s chest to protect her, then donned a gas mask.

“Hummmmm~” The Destroyer micro-drone emerged from the void.

“Xiao Yue, guard Butterfly Kanae. I’ll handle the rest.”

“Understood. Engaging combat mode. Drone control authority acquired!”

“Cough… Zero… be careful… cough… he’s an Upper Moon… his attacks carry ice poison… don’t inhale…” Butterfly Kanae gasped through searing lung pain.

“I know. Stay put.”

Dōma recovered from the explosion, staring at his shattered fan and the masked figure wielding a strange weapon, his curiosity piqued.

Zero also noticed the numbers in Dōma’s eyes: “Upper” on the left, “Two” on the right. As he observed Dōma’s movements, he used his Analysis Glasses to study the effects of his Blood Demon Arts.

“Oh my! What an incredible weapon! You shattered my fan—and even hurt me! Tell me, what is this weapon? Are you one of the Demon Slayer Corps’ Pillars? What’s your name?” Dōma, having already healed his wounds, chattered cheerfully to Zero.

“So tedious,” Zero thought, but his hands never paused.

Boom! Boom! Boom!

Having already experienced the bullet’s power, Dōma swung his remaining fan and activated a Blood Demon Art to block.

“Blood Demon Art: Crystal Child.” Dōma created five ice dolls from ice crystals.

Zero, through prior analysis, knew these were autonomous ice dolls modeled after Dōma himself. Though small, they possessed formidable combat strength and could replicate his master’s Blood Demon Arts.

The five ice dolls blocked the three bullets and shattered, leaving two that swiftly advanced toward Zero. Zero reacted instantly—two cross-shaped Nano-Alloy Hover Cannons materialized before him, intercepting the ice dolls.

“Thud… thud…”

The two ice dolls slammed into the hovering cross-shaped cannons emerging from the void, attempting to flank—but were consistently blocked.

Zero swiftly stowed the Nano-Alloy Annihilation Sniper and switched to the Nano-Alloy Model Four. Though the Sniper had devastating destructive power, its sole flaw was a 1.5-second charge time between shots. Though brief, that delay could turn the tide of battle.

“Blood Demon Art: Lotus Ice.”

“Blood Demon Art: Vining Lotus Blossom.”

The two ice dolls activated their Blood Demon Arts.

One swung its paired fans, spraying lotus-shaped ice crystals.

The other conjured multiple ice vines entwined with lotus blossoms, attempting to bind Zero.

All were blocked by the hover cannons.

Zero drew the first and second modules of the Nano-Alloy Model Four, infused them with energy crystals, and felt a surge of heat as he slashed at the two ice dolls.

The ice dolls instantly melted from the heat. Zero kicked off the ground with his right leg and charged toward Dōma.

“Blood Demon Art: Abyssal Winter Pillar.” Seeing his Crystal Children fail to stop this strange opponent, Dōma activated another Blood Demon Art.

Ice spikes formed above Zero’s head—but he did not halt. He continued swinging his first and second modules, slashing at Dōma.

“Tatata-tatata-tatata~”

Far away, Xiao Yue, guarding Butterfly Kanae, operated the Destroyer drone to shatter the hovering ice spikes.

Xiao Yue and Zero’s Moqi had long reached a level of perfect synchronicity.

Dōma shed his playful demeanor and finally grew serious.

But Zero would not give him any opening—he charged forward, relentlessly swinging his weapons, refusing Dōma any chance to counterattack.

“Ding! Ding! Ding!”

“Bang!”

The sword-fan clashed repeatedly, sparks flying, as Doumo was steadily forced backward.

“Blood Demon Art: Vine Lotus.”

Instantly, several ice vines erupted around Doumo and surged toward Zero, who swiftly swung his weapon, severing and melting them all.

Yet, even as Zero eliminated the ice vines, Doumo seized the opportunity to strike swiftly.

“Thud. Thud.”

High-temperature bullets fired from the ends of Zero’s cross-shaped dark alloy floating cannons slammed into Doumo. Forced to defend, Doumo blocked with his fan.

Far away, Kanae Kocho watched the battle between Zero and Doumo in disbelief.

“That’s an Upper Rank demon—he’s holding his own against him, even dominating him!” Kanae Kocho thought, her eyes burning with fervor. If he joined the Demon Slayer Corps, they could protect far more people from evil demons.

Even if I die now, I’ll have no regrets—only that I can no longer walk beside Shinobu.

“Hng!”

“Splat! Splat!”

One of Doumo’s hands and one of his feet were severed. He felt his limbs suppressed—unable to regenerate.

Zero continued swinging his weapon, this time aiming for Doumo’s neck.

“Shhh!”

Doumo leaped backward on his single remaining leg to evade, but a deep gash opened from shoulder to abdomen, blood gushing freely.

Zero saw his strike dodged—no surprise. He pressed forward.

Doumo didn’t understand why, but a sudden wave of fear rose within him. He had never felt emotion since childhood, yet he knew this fear: if he was hit, he would die.

“Blood Demon Art: Mist Ice—Lotus Bodhisattva!” This was Doumo’s ultimate technique, his final trump card—a colossal ice figure formed, resembling a Bodhisattva seated in prayer with hands clasped.

Merely waving its arms unleashed tremendous force, while releasing vast clouds of toxic ice mist.

But since it was hastily created in Doumo’s dying state, its movements were sluggish.

Zero swiftly dodged the Lotus Bodhisattva’s attacks with dual weapons, unimpressed by the ice statue—he had already analyzed Doumo’s Blood Demon Art with his Jiexi glasses and knew this was his last resort.

“You think this can save your life? What a naive child.” Zero inserted his first and second blades into their sheath-holster, stepped back, and retrieved the Dark Alloy Annihilation Cannon Sniper from his nanospace. He aimed it at Doumo, shielded within the ice Bodhisattva.

“Bang! Bang! Bang!”

Multiple shots fired—the ice Bodhisattva could not withstand the cannon’s explosions; cracks spread across its surface.

“Heh, still resisting? Try this: Cluster Detonation!” This was a capability Zero had built into the Dark Alloy Annihilation Cannon Sniper—concentrating energy to fire a bullet with ultra-penetrating explosive damage.

“Boom!” A deafening blast erupted, sending violent shockwaves radiating outward. Far off, Kanae Kocho felt her eardrums ache—had it not been for her quantum shield, the vibration would have worsened her injuries.

“Shhh! Boom!”

“Puff!” Doumo spat a gout of blood. The Cluster Detonation bullet pierced through the ice Bodhisattva, shattering it instantly—and passed through Doumo’s body, exploding a gaping hole in his chest.

“So this is what death feels like… how strange.” Doumo lay on the ground, still unrecovered, gazing at Zero.

Just as Zero prepared to fire again and eliminate Doumo, a harp melody sounded.

“Zheng!”

Instantly, a door opened beneath the ground where Doumo stood, pulling him to safety.

“Don’t you dare run!”

“Bang!”

Zero fired one last shot as the door began to close—but it was too late. The bullet struck the ground and exploded, leaving a massive crater.

“Tch. Lucky you. Next time I see you, I’ll tear you into a thousand pieces!” Zero said.

He retracted all his weapons into nanospace, removed his gas mask, and approached Kanae Kocho, taking off her quantum shield.

“Zero… you… cough… I’m afraid I don’t have much time left. Please… tell my sister… I can’t walk beside her anymore… cough.”

“And… please… tell my sister… she looks beautiful when she smiles. I hope she… keeps smiling through life. And if you can… I wish you’d join the Demon Slayer Corps… cough.” Kanae Kocho, sensing her end near, spoke her final words and wishes.

“You tell her yourself! Xiao Yue, find me a place nearby to rest—I need to heal her!”

“Master, we can go to the Kijō family’s home. It’s not far—about twenty kilometers away!” Xiao Yue replied.

“Understood.” Zero retrieved a light-energy flyer from nanospace, strapped it to his back, inserted an energy crystal, and unfolded its wings.

Kanae Kocho was stunned into silence, staring at the wings unfolding behind Zero—one black, one white—lifelike under the moonlight, shimmering with flowing light, as if fused from angelic and demonic wings.

“Xiao Yue, squeeze into my pocket for now! We need to move fast!” Zero pointed to the pocket on the left side of his coat, signaling her to hide there.

“Yes, Master!” Xiao Yue slipped into the pocket, gripping its edge with both hands, her head peeking out.

Zero lifted Kanae Kocho into his arms and flew toward the Kijō residence.

Kanae Kocho’s face flushed crimson to her neck; she dared not look at Zero. She had never been held by a man before—let alone carried in a princess hold.

…

Hours later, the sky began to lighten with the first pale glow of dawn.

Shinobu received a distress call from her sister’s war cry crow: her sister had encountered an Upper Rank demon.

Every Demon Slayer Corps Pillar who faced an Upper Rank demon had died without exception.

“Sister, hold on—I’m coming!” Shinobu said.

When she arrived, the ground was pockmarked with craters, littered with shattered ice and bloodstains, the air thick with gunpowder.

But Shinobu cared nothing for the destruction—she searched desperately for her sister’s figure, refusing to believe she was gone.

Shinobu called out as she searched.

“Sister, where are you? Sister! Sis…” Her voice broke as she spotted a broken sword half-buried in the dirt. She picked it up—it was her sister’s Nichirin Blade. But her sister was nowhere to be found.

Staring at the broken Nichirin Blade, Shinobu faced a truth she could not accept.

“No… this… this can’t be! It can’t be! Sister, where are you? Come out! Don’t scare me! Waaah… Sister…” Shinobu could not believe it—she convinced herself her sister was merely gravely wounded, unable to respond.

“Why… why is this happening?! Didn’t fate take enough from me? Now it takes my sister too?! Waaahhh…” Shinobu knelt on the ground, clutching the broken blade, weeping uncontrollably.

Soon after, another Demon Slayer arrived.

A towering monk-like giant, over two meters tall, with a long scar across his forehead and blind eyes, draped in a brown kasaya embroidered with “Namu Amida Butsu.”

He was the Stone Pillar of the Demon Slayer Corps—Himejima Gyomei.

“Namu Amida Butsu… even the Flower Pillar…”

“Master Himejima, my sister…”

Himejima Gyomei did not know how to comfort Shinobu. Losing a Pillar was a devastating blow to the Corps.

“Let us return to Corps Headquarters and inform the Lord. We will avenge the Flower Pillar! Namu Amida Butsu.” Himejima said.

“I will kill the demon who took my sister myself—I will avenge her!” Shinobu snarled.

…

Time returned to the night.

Zero carried Kanae Kocho to the Kijō residence in one minute. Kujō Matsui was stunned by the wings behind Zero.

“Quickly, prepare a room. I must heal her. She’s critically wounded—if you don’t treat her now, she’ll die!” Zero commanded.

Only then did Kujō Matsui notice the girl in Zero’s arms—he recognized her: Kanae Kocho, the Flower Pillar. But her condition was dire—pale face, bloodied clothes.

“What are you standing there for? Move!”

“Ah! Yes, my lord! Please, follow me!”

Under Kujō Matsui’s guidance, they entered a clean, prepared room.

Zero laid Kanae Kocho on the tatami, turned to Kujō Matsui, and said: “I’m going to heal her. Stand guard at the door. Let no one disturb me.”

“Yes, my lord. Do you need anything else?”

“Nothing. Just guard the door. No interruptions.”

“Understood, my lord.” Kujō Matsui bowed and left, closing the door and standing watch.

Zero knelt beside Kanae Kocho. “Kanae Kocho, I’m going to treat you now—but I must explain something first, so you don’t misunderstand.”

“What is it?” Kanae Kocho whispered weakly, lying on the tatami.

“I need to remove all your clothing.” The moment he said it, the air grew awkward.

Kanae Kocho blushed furiously, her entire face burning red.

“I… I suppose… you… you can help me take them off. I have no strength left. And… call me Kanae.” She turned her face away, refusing to look at Zero.

“O… okay.” Zero closed his eyes, propped her up with his arms, and began removing her haori, then unfastening her garments—but his hands brushed against other parts of her body.

“Ah~?”

Zero: “???!!!”

“You… you should open your eyes and help me!” Remembering her own cry, Kanae felt unbearable shame—as if she’d done something improper.

“But… that…”

“I’m the patient. You’re the doctor. Don’t be so timid. If it helps, treat me like a female doctor.”

“…Fine.” Zero opened his eyes and began undressing Kanae.

Soon, he stared at Kanae Kocho, completely naked—her skin pale, delicate, flawless. Unbidden, strange images flashed through his mind.

Kanae Kocho covered her vital areas with both hands, head bowed, unable to meet his gaze. This was the first time she had ever been seen naked by a man—and yet, an unfamiliar warmth stirred within her, her heartbeat quickening.

Zero shook his head sharply, banishing the thoughts, and retrieved a healing pod from nanospace.

Kanae Kocho was stunned again by the white machine before her.

“This is a healing pod I designed. It will rapidly treat your injuries. I’m placing you inside now.”

“Mm.”

Zero opened the pod’s lid, lifted Kanae Kocho once more in a princess hold, and gently placed her inside.

"Now, get a good rest inside. You’ll recover in no time. Don’t worry—nothing will happen to you!"

"Mm, thank you, Zero."

He closed the lid and, through the glass panel, saw Butterfly Kanae inside.

Butterfly Kanae, through the glass, saw Zero outside and smiled faintly—a smile that seemed deeply healing.

Zero glanced at the data displayed on the recovery chamber’s panel.

【Butterfly Kanae: Severe injuries, frostbite, poisoning, alveolar damage】

【Treatment duration: 5 hours.】

【Energy crystal consumption required: 60.】

Without hesitation, he inserted 60 energy crystals. Instantly, a white glow filled the chamber. Butterfly Kanae felt the warmth and soon fell into deep sleep.

Having finished, Zero sat on the tatami. Xiao Yue flew out of his pocket.

"???, Master, how do you feel?"

"How do I feel about what?"

"Her figure! Even I think she’s beautiful—pale and soft! I’ve seen her, touched her… Ouch! Master, why did you hit me?!" Xiao Yue was mid-sentence when Zero lightly flicked her forehead.

"Who taught you this? Was it Luo Li, while I was asleep?"

"N-no! Hehe! Let’s not talk about that—Master, how strong was that demon?" Xiao Yue quickly changed the subject, afraid Zero might flick her again—even if he didn’t use much force.

"If we judge by the Mother Void Worm’s subordinates, that demon is only low to mid-tier. I could kill it. But here, the world’s dimensional suppression limits my power to half."

"Then what are your plans next?" Xiao Yue asked, perched on Zero’s shoulder.

"We’ll see… For now, while Kanae is recovering, let’s rest properly."

"Mm."

…