Chapter 49

My name is Zero.

Zero Pillar of the Demon Slayer Corps.

Sometimes I wonder if everyone in the Demon Slayer Corps has gone through all sorts of strange things.

For example, right now…

I just woke up to find Kanao and Mitsuri sandwiching me between them in bed, while Xiao Yue was lying face-down on my chest, leaving me completely immobilized…

Kanao was fine—she was just holding one of my arms while sleeping, smiling sweetly, probably dreaming something pleasant.

Xiao Yue, like a tiny doll, lay quietly asleep on my chest.

But Mitsuri…

She clung to me like an octopus, arms wrapped tightly around my head, giving me two face creams before breakfast…

And she kept mumbling in her sleep…

“Zero… hehe… don’t move… I’ll take care of it… hehe~”

“So big… can I even fit this in?!”

“Zero… no no… da mei da mei~”

Zero: ?_? Wait, what dream was she having? Why do I feel so weird…

In her dream, Mitsuri was feeding Zero a huge bowl of noodles; Zero tried to take the chopsticks himself, but Mitsuri stopped him.

Finally, the chef made an extra-large tricolor glutinous rice ball, and Zero picked it up to feed it to Mitsuri…

(???? Is someone imagining something lewd?!

“Such a mix of pain and pleasure…” Zero sighed helplessly in his heart.

Waking up to such a sensual scene first thing in the morning left Zero with a strange sensation—something inside him seemed to be burning, uncomfortable.

Without disturbing Xiao Yue, Kanao, or Mitsuri, he gently pulled his arm free from Kanao’s grasp, adjusted Mitsuri’s sleeping posture, lifted Xiao Yue, and placed her on Kanao’s chest, then got up alone.

Today, there was something important to do: he needed to organize all the information about Muzan Kibutsuji, the Upper Moons, and the Infinite Castle.

He left the room wearing only a white shirt and shorts.

The shirt was long enough to cover the shorts; without close inspection, one might think he was wearing nothing but the shirt.

Combined with his delicate features and untrimmed long white hair, he could easily be mistaken for a girl—purely a morning temptation…

He scratched his head, and the inner agitation slowly subsided: “This is such a headache!”

“Zero, up so early?”

Kamado Kie was busy in the kitchen and greeted him.

“Yes, Auntie Kie, I have some tasks today.”

“You’re working so hard. Breakfast will be ready soon—go freshen up first.”

“Auntie Kie, you don’t have to wake up so early every day. You could sleep longer.”

“How could I? You saved me and my children, and you took us in. What I do is nothing.”

“Alright, but take care of yourself. Don’t wear yourself out.”

“Don’t worry—I won’t. Go wash up now.”

…

After washing up, Zero ate breakfast with Kamado Kie and her children, then returned to his room to begin organizing the intelligence.

Kanao and Mitsuri also woke up at this time, ran over, and each gave Zero a light kiss on the cheek.

Xiao Yue floated in midair, watching the three, a knowing smile on her face.

“You two lazybones, go wash up and eat something. I have something to tell everyone soon. Xiao Yue, eat something too—replenish your energy.”

“Okay~” x3

After the three left the room, Zero took out the [Analytical Glasses] and a notebook from his [Nanospace], preparing to record all the information.

Fortunately, that day he activated the [Analytical Glasses] and recorded all the battles, saving him considerable effort.

Otherwise, writing everything down by hand would have taken far too long.

He sat at the desk and activated the projection mode.

First, he reviewed the information on [Upper Moon One].

【Name: Kokushibo—Demon Samurai】

【Human Name: Kyojuro Rengoku】

【Rank: Upper Moon One of the Twelve Kizuki】

【Partner: Muzan Kibutsuji】

【Age: 480 years】

【Younger Brother: Kyojuro Rengoku】

【Descendant: Muichiro Tokito】

【Abilities: Breathing Mark, Transparent World】

【Breathing Style: Moon Breathing】

【Weapon: Demon Blade—Kyokujitsu Shinjo】

【Personal Info: The strongest Upper Moon among the Twelve Kizuki. In his human life, he was known as Kyojuro Rengoku, the eldest son of the Kyojuro clan, a samurai family during the Sengoku period, and the twin brother of Kyojuro Rengoku.】

“My earlier guess was right! Including his breathing style… heh…”

…

He took a deep breath, turned to the page in his notebook recording [Muzan Kibutsuji] and the [Twelve Kizuki], crossed out “Kyojuro Rengoku” beneath “Upper Moon One,” and wrote “Kokushibo.”

After recording this, he used the [Analytical Glasses] to search for all information related to [Moon Breathing].

He did this merely as a precaution—though he had already witnessed Kokushibo’s Moon Breathing, he remained cautious.

【Searching… Search successful】

“As expected—only by encountering it can the [Analytical Glasses] record and analyze it… Let’s see this Moon Breathing!”

【Moon Breathing: One of the derivative breathing styles of Sun Breathing. Sun and Moon shine together, moonlight gleams brilliantly. Slightly weaker than Sun Breathing, yet stronger than the Five Great Breathing Styles!】

【Composed of sixteen forms. The first six can be performed by a human body; the last ten would cause unimaginable self-injury if attempted by a human.】

【Moon Breathing Techniques】

【Moon Breathing. First Form: Dark Moon—Yoi no Miya】

【Moon Breathing. Second Form: Pearl Blossom Dancing with the Moon】

【Moon Breathing. Third Form: Loathed Moon—Erosion】

【Moon Breathing. Fourth Form…】

【Moon Breathing…】

Zero carefully studied every technique of [Moon Breathing], recording and analyzing their attack patterns.

The further he read, the more stunned he became.

Not because of anything else—just wondering if the Demon Slayer Corps’ Pillars could possibly withstand this.

If things continued like this, even if they all attacked together, they’d be wiped out instantly!

“No wonder the records say Kokushibo is the strongest Upper Moon—he truly is!”

He thought for a moment, recalling Kokushibo’s blade, and felt something was off about it.

He clicked on the floating projection, located the two appearances of Kokushibo’s blade, and analyzed them.

【Analyzing… Analysis successful】

【Weapon: Demon Blade—Kyokujitsu Shinjo】

【Description: This demon blade was forged from Kokushibo’s own flesh and blood.】

【The blade, hilt, and grip are covered in eyes; each swing releases countless crescent-shaped blades whose size and length constantly shift, with no fixed form.】

【If damaged, the blade instantly regenerates to its original form, and as Kokushibo unleashes his true power, it evolves into a longer, multi-bladed aberration.】

“So that’s how it is~”

“No wonder his attacks became so widespread and piercing when we fought again in the Infinite Castle!”

He turned back to Kokushibo’s personal information.

【As a human, Kokushibo was known as Kyojuro Rengoku, born during the Sengoku period, the heir of the Kyojuro samurai clan, with a twin brother named Kyojuro Rengoku.】

【In the Sengoku period, twin siblings in samurai families were considered an ill omen, as they would compete for inheritance upon adulthood. Upon their birth, because Kyojuro Rengoku was born with a strange “birthmark” (Breathing Mark), their father intended to kill him immediately.】

【But due to his mother’s furious, near-mad intervention, the younger brother survived. Yet according to tradition, the father still chose the eldest son, Kyojuro Rengoku, as heir, and forced Kyojuro Rengoku to become a monk at age ten…】

“So Kyojuro Rengoku’s [Breathing Mark] is exactly as I suspected—[Congenital Breathing Mark]… heh, how superstitious that era was!”

His gaze continued to the projection screen.

【As the family heir, Rengoku lived a life vastly superior to his brother’s from childhood. Seeing Kyojuro Rengoku constantly clinging to their mother’s left side, young Rengoku believed his brother was emotionally dependent on her due to unfair treatment, and thus felt pity for him.】

【To comfort his brother, Kyojuro Rengoku secretly visited Kyojuro Rengoku’s tiny three-mat room, hiding it from their father.】

【Later, their father discovered Rengoku’s forbidden contact with Kyojuro Rengoku and brutally beat him in public. But Kyojuro Rengoku never distanced himself from his brother.】

【Since giving Kyojuro Rengoku his own belongings risked discovery, Rengoku carved a flute himself and gave it to his brother, saying, “Whenever you need me, blow this flute—I’ll come right away.” Then, bruised and swollen from his father’s beating, Rengoku gave his brother his most sincere smile.】

【Because Kyojuro Rengoku had never smiled or spoken since birth, Rengoku once mistakenly believed his brother was born deaf and mute.】

【But everything he thought about Kyojuro Rengoku was utterly overturned when he turned seven…】

【One day, while practicing swordplay in the courtyard, Rengoku noticed Kyojuro Rengoku watching him from beneath the tree’s shadow.】

【Then, suddenly, Kyojuro Rengoku spoke: “Brother, your wish is to become the strongest warrior in this country? Then I will become the second strongest.”】

【Rengoku froze in shock—his brother had spoken fluently for the first time.】

【But after recovering, Rengoku thought about his brother’s words and found them ridiculous.】

He was destined to be sent to a temple as a monk after turning ten, yet he always clung to his mother, whining like a coward—such a weakling could never become a warrior.

Then, Kyojuro Rengoku smiled for the first time, but Kyojuro Rengoku found his brother’s smile inexplicably repulsive; after that, whenever Rengoku practiced swordsmanship, Rengoku would always watch from the side…

Seeing this, Zero fell into thought…

“It must be because Kyojuro Rengoku frequently watched Kyojuro Rengoku practice swordsmanship, and under some subsequent circumstance, he displayed unparalleled talent, causing their father to change his view of Kyojuro Rengoku—and indirectly planting one of the roots of Kyojuro Rengoku’s jealousy!”

Thus, he continued reading the information about Kokushibo’s human past.

【One day, Kyojuro Rengoku suddenly requested that his father’s subordinate, who trained Kyojuro Rengoku, teach him swordsmanship.

The subordinate, jokingly, handed Kyojuro Rengoku a bamboo sword, verbally taught him some basic sword techniques, then told him to attack.

But everything changed right then! The first time Kyojuro Rengoku swung his blade, he struck only four times and effortlessly knocked down the subordinate—whom Kyojuro Rengoku had never defeated.

Witnessing this firsthand, Kyojuro Rengoku realized his brother, whom he had always pitied, was a genius.

Yet after that, Kyojuro Rengoku never again expressed a desire to become a warrior. From Kyojuro Rengoku, Kyojuro Rengoku learned that he didn’t want to be a warrior because he disliked the feeling of striking others.

But Kyojuro Rengoku always wanted to know the secret behind his brother’s strength.

Finally, after relentless questioning, Kyojuro Rengoku revealed something Kyojuro Rengoku could not understand: when facing an opponent’s attack, his lungs would move violently; all he needed to do was observe the opponent’s internal physiological signs.

After spending time to comprehend it, Kyojuro Rengoku finally realized that in Kyojuro Rengoku’s eyes, all living beings were transparent!

His innate talent far surpassed his own, and his body was strong enough to bear it—he was truly “a person favored by the gods.”

Kyojuro Rengoku, who had always dreamed of becoming a great warrior, felt overwhelming helplessness… Though his own talent was decent, and he could improve through effort.

But every achievement earned through effort paled beside his brother, the true chosen one—like the slow crawl of an ancient tortoise, utterly incomparable.

Thinking of this, Kyojuro Rengoku began to curse heaven’s injustice! Why didn’t heaven grant such talent to those who needed it?!

At the same time, Kyojuro Rengoku began to foresee his own fate: his position would be completely reversed from his brother’s—Kyojuro Rengoku, with far superior talent, would be favored by their father and inherit the family; while he himself would be banished to a tiny three-mat room, waiting silently until ten, when he’d be sent to a temple, never to become the warrior he longed for…”

Of course—Kyojuro Rengoku was the chosen one in this world. His innate spot pattern and Transparent World... it all began right here, planting the seed of jealousy in Kyojuro Rengoku’s heart!

“What a cruel twist of fate…”

【One day later, Kyojuro Rengoku suddenly came knocking on Kyojuro Rengoku’s bedroom door and, sorrowfully, told him of their mother’s death.

Before Kyojuro Rengoku could react—or even feel grief—Kyojuro Rengoku immediately told him he would soon become a monk, and that he would cherish the flute Kyojuro Rengoku had given him, just as he cherished his brother.

Then, Kyojuro Rengoku watched his brother smile while caressing the flute.

He couldn’t understand why his brother treasured such a broken flute that couldn’t even produce a proper note. But Kyojuro Rengoku said nothing, watching his brother’s joy, his heart filled with resentment toward him.

After Kyojuro Rengoku left home, Kyojuro Rengoku discovered from his mother’s diary that years earlier, she had already lost sensation in her left side due to illness.

At that moment, Kyojuro Rengoku suddenly recalled how Kyojuro Rengoku had always leaned against his mother’s left side—and realized the truth! Kyojuro Rengoku had known all along about his mother’s condition; his closeness to her had never been for affection, but to support her frail body.

Suddenly realizing he had never, in any way, matched Kyojuro Rengoku, Kyojuro Rengoku’s jealousy sank deep into his bones.

From then on, the brothers’ bond was severed by an insurmountable wall called talent…”

Seeing this, Zero began his dark inner mockery of Kokushibo: “Poor, pitiful Kyojuro Rengoku... heh heh... overflowing with jealousy. No wonder I was so furious when I said that!”

“From now on, whenever I meet you, Kokushibo, I’ll call you ‘Six-Eyed Lemon Spirit’—perfect!”

After mocking Kokushibo internally, he continued reading.

【Later, their father learned of Kyojuro Rengoku’s talent and regretted his decision, sending men to the temple to bring him back.

But the reply came: Kyojuro Rengoku had never gone to the temple. The brother Kyojuro Rengoku had always despised had vanished without a trace…

After that, over a decade passed. By then, Kyojuro Rengoku had inherited the family’s legacy, married, and had children. His life was comfortable, yet inexplicably dull—as if time itself had slowed.

One day, while leading his troops on campaign, Kyojuro Rengoku’s army set up camp in a forest when they were unexpectedly attacked by demons. All were killed except Kyojuro Rengoku himself.

Just as he was about to be killed, the unthinkable happened! Grown into a man, Kyojuro Rengoku suddenly appeared and saved him, effortlessly slaying the demon.

Stunned and frozen in place by his brother’s power, Kyojuro Rengoku received only his brother’s calm apology.

Seeing his brother’s mastery, Kyojuro Rengoku’s hatred and jealousy reignited.

Later, to obtain the power Kyojuro Rengoku possessed, Kyojuro Rengoku abandoned his family and children, becoming a demon slayer like his brother, joining him in the hunt against the demon progenitor, Muzan Kibutsuji.

When Kyojuro Rengoku taught the Breath Techniques to other Demon Slayers, Kyojuro Rengoku, unable to withstand the power of the sun, could not master the Sun Breathing, and was forced to use the inferior Moon Breathing.

Though bitter, as he refined his command of the Breath Techniques, Kyojuro Rengoku eventually awakened the same mark as Kyojuro Rengoku. With greatly increased power, he began to wonder: if he continued training, could he surpass Kyojuro Rengoku…?”

“Huh? This is…” Seeing this, Zero quickly flipped open his notebook to the page recording 【Kyojuro Rengoku】 and compared it carefully.

“Kyojuro Rengoku was supposed to be sent to a temple at ten—but he never went… If I’m right, at that moment, when he left for afar, he met his other half…”

“Now, combined with my earlier guess, it all fits!”

Understanding it all, his gaze returned to the projection screen.

【As time passed, Kyojuro Rengoku noticed his companions who had awakened the mark were dying one by one, eventually realizing that anyone who awakened the mark would not live past twenty-five.

He was about to turn twenty-five himself. Kyojuro Rengoku realized he had no time left to further hone his swordsmanship—and felt profound confusion.

Soon after, during a pursuit of Muzan, Kyojuro Rengoku directly encountered Muzan.

In direct, one-on-one combat with Muzan, Kyojuro Rengoku’s inner fears were exposed.

Faced with Muzan’s offer to become a demon and gain infinite time to perfect his swordsmanship, and influenced by his soul-deep jealousy toward his brother,

Kyojuro Rengoku ultimately could not resist the temptation. He drank Muzan’s blood, spent three full days transforming into a Demon of the Sword, and became the first Upper Moon—Kokushibo…

Later, the Kyojuro family declined after his transformation. His descendants, forced to flee persecution, hid in the mountains and changed their surname to Tokitō, living for generations as woodcutters.”

The information ended here. After reading it, Zero frowned slightly, his loathing for Kokushibo growing.

What would his descendant—the Mist Pillar, Tokitō Muichirō—think if he learned all this?

The decline of the Kyojuro family was caused by Kyojuro Rengoku himself…

He abandoned his family—even his wife and children!

All because he was jealous of his brother, Kyojuro Rengoku!

To surpass him, he even became a demon… Hah… Kyojuro Rengoku—no, Kokushibo now—is a joke!

He opened the page for 【Kyojuro Rengoku】 in his notebook, thought for a moment, and wrote at the bottom right: 【Kyojuro family’s decline—caused by Rengoku alone.】

After thinking again, he wrote beneath 【Kyojuro Rengoku】: 【Lemon Spirit】

Then he took several blank sheets and recorded some of the most important information on them.

Having done this, he began searching for information on other Upper Moons.

………