Isekai Adventure in the Dimensional Cube

Just as Reiger began his quest for the hidden blade sheath, a conversation was taking place in the Demon Slayer Corps headquarters, within the Ubuyashiki family estate.

The location was the same courtyard where Reiger had last met with Ubuyashiki Kagaya.

"Has Tsukiguni Yoriichi's training finally ended?"

Ubuyashiki Kagaya once again arrived at the corridor connected to the courtyard, listening to the report of Kochou Shinobu, who was kneeling on one knee before him, and murmured to himself.

"Yes," Kochou Shinobu, with her eyes closed and a smile on her face, reported while bowing her head, "These are the words from Yoriichi himself, so there can be no mistake."

"That's good," Kagaya asked in a warm tone, "So what do you think, how did Tsukiguni Yoriichi's training fare this time?"

Faced with this question, Kochou Shinobu replied without hesitation.

"It should be as you wish."

What this statement implied could probably only be understood by Ubuyashiki Kagaya and the pillars themselves.

The implication of Kochou Shinobu's words was that the phrase Kagaya had spoken here last time was not just empty talk.

"Really? You think so too?"

Kagaya seemed very pleased.

"I have no choice; as one who has witnessed the results of that training, I can't imagine anyone who could defeat Lord Yoriichi," said Kochou Shinobu softly, "If our enemy is stronger than Yoriichi in that state, it would truly be despairing."

Kochou Shinobu laid it out that far.

She truly believed that if their enemy was stronger than Reiger, then the Demon Slayer Corps might as well disband on the spot, for it was impossible for humans to win against such a monster.

But conversely—

"If our enemy is not as strong as Lord Yoriichi, the long-standing wish of the Demon Slayer Corps, in our generation, might be the closest ever to fulfillment."

At this point, a complex and hopeful emotion couldn't help but show in Kochou Shinobu's eyes.

"It will happen."

Kagaya then spoke with finality.

"We have finally seen the opportunity to end all this arise; we must put an end to all the tragedies in our generation."

"The stain of the Ubuyashiki clan, the humiliation we bear, also must be cleansed in this generation."

"This time, we must kill him."

Kagaya's voice rose tenderly.

"We must kill that Demon King, Kibutsuji Muzan."

Upon hearing this, Kochou Shinobu bowed her head again.

"Yes."

The response echoed in the courtyard, lingering for a long time.

......

At the same time, in a deep mountain not far from the Ubuyashiki family estate, several people were moving some items, transporting them in the direction of the small town.

They wore a uniformed outfit, their faces covered with masks, somewhat resembling operatives of a covert agency.

Indeed, that was the case.

These people were the 'hidden'.

The so-called hidden is the after-action processing team of the Demon Slayer Corps, specifically responsible for the aftermath of battles between Slayers and demons and various non-combat matters.

In other words, the hidden are non-combat personnel of the Demon Slayer Corps' logistics team, mostly consisting of members without swordsmanship talent, having similar recruitment conditions to the Butterfly Mansion, both supporting the Corps from behind the scenes.

At this moment, several members of the hidden were transporting a batch of supplies to Demon Slayer Corps Headquarters.

"Be careful not to bump into anything; everything here is the livelihood supplies for our Lord and the pillars."

"Are these to be taken directly to the estate?"

"Who will switch with me?"

They cautioned one another while heading towards the town.

However, among these people, someone soon detected something unusual.

"What is that?"

A cart-pushing member of the hidden pointed at the mountain path ahead, exclaiming in surprise.

Everyone looked in unison.

"A jar?"

"Is that a jar?"

"Why would a jar appear in the middle of the road?"

The members of the hidden looked at each other, puzzled.

Just as they had said, there was a jar in the very middle of the mountain path.

The jar looked rather exquisite, already out of place in such an old mountain trail, to say nothing of its standing right in the middle of the road, making it seem strange and abrupt.

"Whose jar is this?"

A member of the hidden began to approach with some impatience, intending to move the jar aside.

But in that instant, something astonishing happened.

"Whoosh!"

Suddenly, a hand shot out from the exquisite jar, grabbed the member's head, and dragged him into the jar.

"Splurt!"

A spray of blood exploded at the mouth of the jar, and the man's scream began sharply, then abruptly ceased, leaving no signs of movement.

"What...!?"

"Is it a demon!?"

"It's a demon! The demon is here!"

The remaining few immediately fell into a state of panic, reflexively fleeing to distance themselves from that pot.

Unfortunately, as soon as they all bolted into the bushes, it didn't take long for a series of screams to follow one after another, only becoming quiet after a while.

By then, a person covered in blood had also climbed out of that pot.

"Ssss, looks like I've caught a big fish this time," he said while covering his mouth and giggling.

Instead of a blossoming young girl, the one who chuckled sneakily was a particularly ugly monster.

His whole body was pale white, resembling a squirming fish, with purple fins on his head. His mouth was located where the eyes should be, eyes positioned on the forehead and above the mouth, with yellow eyeballs and green lips. He had several small arms growing out of his head and body—he was a complete monster, lacking any of the characteristics assigned to humanity.

Upon closer inspection, there were characters inscribed within the eyes on his forehead and mouth.

One eye was inscribed with—"Five."

Another eye was inscribed with—"Upper Moon."

He was none other than Gyokko, the Upper Moon Five of the Twelve Demon Moons.

"I never imagined, never imagined that while following Lord Muzan's orders to track down that swordsman named Tsukiguni Yoriichi, we would stumble upon the Demon Slayer Corps Headquarters in the process. What a great feat indeed, ssss."

Gyokko twisted his body in high spirits and called out in the direction of the bushes.

"Don't you think so, Hantengu?"

Following Gyokko's extremely excited voice, a figure slowly emerged from the bushes.

It was an old man with eyes rolling back, unseen numbers within, a swollen forehead, horns on his head, his face as ferocious as a demon mask.

"Terrifying... truly terrifying..."

Named Hantengu, the old man trembled violently as he prostrated on the ground and spoke.

"We were originally facing just one opponent, but now it's the entire Demon Slayer Corps. It's too terrifying, eee."

Hantengu appeared as though he was about to cry on the spot from fright.

"Well, if you're going to say that, then I guess I'll have to gobble up all the credit for this mission by myself, can I? Ssss!"

Gyokko stuck out his long tongue, twisting it around as he laughed.

"Eeee..." Hantengu curled into a ball on the ground, his voice quivering, "Are you bullying me too? Bullying this weakling? Horrible! So horrible!"

"Ssss!" Gyokko licked his lips and said with a laugh, "Don't joke around, Hantengu. You are a demon that possesses a number higher than mine. You can hardly be considered weak, right?"

"Eeee." Hantengu hid within the bushes, trembling as if he hadn't heard Gyokko's words, "We need to report this to Lord Muzan, then Lord Muzan will protect me, this weak one."

"Don't forget to mention my name, okay?" Gyokko called towards the bushes before turning towards the small town, saying with a smile, "It seems my collection will soon be graced with a fine work of art."

"Which pillar shall I use to craft a new pot?"

"I'll have to give it some thought, ssss."

......

"What? You've found the headquarters of the Demon Slayer Corps?"

In the study of a luxurious mansion, a dark and dangerous voice emerged.

"Tracking that human who claims to be Tsukiguni Yoriichi has led you to the main base of the Ubuyashiki family, has it?"

The person in the darkness snickered.

"Good, the Demon Slayer Corps has been nothing but flies buzzing around me for many years. It's time to obliterate this eyesore."

After musing for a moment, the person then addressed the void, saying,

"Hantengu, you and Gyokko are to stand by there; I will send Daki to your side."

"The main base of the Ubuyashiki family, the headquarters of the Demon Slayer Corps, likely has a few pillars in residence. If there are too many pillars present, the two of you might let someone slip through your grasp."

"This time, with three of you acting together, bring me the heads of the Ubuyashiki, and don't disappoint me."

As the chilly voice faded, so did Hantengu's in the mind of the speaker.

"As you command, Lord Muzan."

The obsequious voice then disappeared.

"Ubuyashiki..."

In the study, a voice filled with rage whispered, echoing ominously.

"This time, you're done for."

......

"Lord Muzan has ordered us to stand by and wait for Daki's support, eee," said Hantengu...

In the deep mountains, Hantengu emerged again, half his body out, calling out towards Gyokko with a series of eee's.

"Daki? That useless oiran?" Gyokko stopped twisting his body, speaking with a tinge of sarcasm, "What is she here for? To get in the way?"

"Eee." Hantengu shrunk back, his voice timid, "It's Lord Muzan's order. To defy it would be terrible, terribly so."

"...Alright then." Gyokko said a bit irritably, "Since even the Upper Moon Six will be joining, this mission will surely be without fail."

"Three Upper Moons joining forces is an event that hasn't happened in a hundred years, never before," lamented Hantengu in a sobbing voice, "The last time more than two Upper Moons assembled together was 113 years ago in that gathering. After 113 years, to have half of the Upper Moons together on one mission... half... three... odd numbers...! Terrifying! So terrifying!"

"Ssss, I'm starting to get excited, you know?"

Gyokko stretched out his arms and resumed twisting his body, his voice growing increasingly exuberant.

"I shall make several works of art while I have the chance."

"Now it's time for work."

"Ssss... ssss... ssss..."

In the darkness, the spine-chilling laughter lingered long, as if heralding the imminent arrival of a tempest.