Demon Progenitor Development Project

The underground of Infinite City.

"when--"

A loud impact echoed through the large, temporarily excavated underground space.

A six-eyed demon wielding a sword stands opposite a giant beast.

(Because Nakime strongly opposed Kokushibo and Fushi Hayabusa fighting in the Infinity Castle, the two demons had no choice but to dig a hole under the Infinity Castle and temporarily create a battleground.)

The Infinite City above was also affected, with the neatly arranged vases and pen holders shaking violently.

Nakime keenly heard the rumbling sound from underground, and immediately felt annoyed. She silently plucked her beloved biwa, moved herself to a higher position, and only stopped when she could no longer hear the sound coming from underground.

Men are so annoying!

All they do is fight and kill all day long!

Fortunately, it wasn't in the Infinity Castle, otherwise Nakime doubted that her Infinity Castle could withstand the antics of these two bastards.

You know, she's an artist who loves the pipa, and this loud noise is really polluting to her ears.

Meanwhile, Kokushibo and Fushun were having a great time fighting.

Upon seeing the giant beast that Fushun had transformed into, Heishibo recognized it as the same beast from Ciwu City.

Soon, Kokushibo realized that he had been spared because of Shugo and the other demons.

Since becoming a demon, Kokushibo felt that the sky was bluer and the water was clearer, and everything looked pleasing to the eye. Most importantly, he had endless time to train and become stronger.

There's just one downside: Kokushibo can't find a sparring partner.

Although he felt that the Demon Slayer Corps had many flaws, there was one good thing about it: there were many swordsmen, so there were many practice targets, and he could hone his skills by hunting demons.

But now that he's a ghost, he can only fight other ghosts, like the Demon Slayer Corps?

Regardless of whether he could find them or not, Kokushibo, after undergoing a buff, felt they were far too weak.

So Kokushibo found Fushi Hayabusa, a demon whose strength was worthy of his attention, and challenged him to a battle.

Fu Jun readily agreed.

As a hired hand with a nominal position, he knew quite a lot of inside information.

Lord Muzan plans to form a subordinate group directly under his command, including powerful demons, and it's rumored that there will be an internal ranking system.

This is also why Fusabune accepted Kokushibo's invitation to fight.

Fushun had no good feelings towards this demon who had once tried to kill him and had even joined the Demon Slayer Corps.

The falcon, now transformed into a giant beast, was panting heavily, covered in wounds, and its eyes held a look of doubt about its existence.

Pillar...is he that strong?

Fu Jun felt like he was about to be hacked to death.

Kokushibo sheathed his sword, quite disappointed. This Fushun was not qualified to be his sparring partner.

It's a challenge level that's somewhat difficult, but not too hard.

It seems I'll have to cultivate on my own, Kokushibo thought.

Fushun was humiliated by the disappointed look in Kokushibo's eyes!

Fu Jun felt suffocated. "You're the one who won! What are you disappointed about? Disappointed that I'm too weak?"

Suddenly, both demons paused; it was a summons from Lord Muzan.

A short while later, the two demons, now fully adorned, appeared outside the room where Muzan Kibutsuji was.

Both ghosts were experienced social creatures; they knew to present themselves properly before meeting the Lord.

To the two demons' surprise, only Shugo was in the room, not Muzan Kibutsuji.

Kokushibo, on the other hand, remained calm and thought it was normal for Shugo to take charge of affairs.

At their first meeting, Muzan Kibutsuji was in female disguise.

He was influenced by the traditional concept that men should be the breadwinners and women should stay at home, so he didn't find it unusual.

However, Shugo was very subtle in his perception, and he always had a strange premonition that he might disappear at any time.

But the falcon is different.

Fusun's expression was subtle. He had seen Muzan-sama's male form and had always believed that Muzan-sama was male.

But what he had seen and heard over the past few months completely shattered his understanding of Lord Muzan.

Cruel, tyrannical, autocratic, and aloof – that's the essence of Muzan Kibutsuji.

How could someone as powerful as Muzan share his power with other demons?

This is truly bizarre!

Fu Jun dared not speak of or even think about the relationship between his two superiors.

"I hope you, Kokushibo, can help me research breathing techniques."

Hiirago said bluntly.

"Researching...breathing techniques?"

Kokushibo was bewildered.

What's the point of studying this?

"To be precise, it's about creating a breathing technique for demons," Shugo explained in detail.

Kokushibo: ... (lost in thought)

"I... can try, but... I'm not sure... there will be... a result," Kokushibo said slowly as always.

Hiiragi nodded.

"It's alright, this is just an experiment. I will also study breathing techniques."

In fact, when he faced Yoriichi Tsugikuni and entered a state of oneness with heaven and man, he 'saw' how the Breath of the Sun worked.

Replicating it isn't difficult; the challenge lies in creating a breathing technique that is universally applicable and also fits the characteristics of an oni.

Shugo doesn't have many requirements; he just needs to fit Muzan's physique.

Even ghosts have their degrees of closeness and distance.

Muzan's potential, which could have been developed in a short period of time, has already been revealed through his recent beatings.

Shugo has already sensed that Muzan's rate of improvement has recently begun to slow down.

Then comes the slow and steady process.

Shugo didn't intend to just wait around, so developing some shortcuts became inevitable.

The breathing technique created by Yoriichi Tsugikuni, the divinely ordained son of God, is a good starting point.

"There's another matter concerning Yoriichi Tsugikuni."

Shugo told Kokushibo about Yoriichi Tsugikuni being expelled from the Demon Slayer Corps.

Kokushibo's eyes flickered slightly, displaying a range of emotions including mockery, contempt, and indifference, but not a trace of regret.

In the end, he simply nodded to indicate that he understood, without further reaction.

"Besides that, there's something else. I plan to meet with Yoriichi Tsugikuni. Would you like to go, Kokushibo?"

Shugo drank a mouthful of Muzan's blood and uttered a shocking statement.

Fu Jun swallowed hard, his eyes gleaming with desire, but he forced himself to suppress his urges and lowered his head.

Kokushibo clenched his fists tightly, and after thinking for a long time, he finally agreed.

He is stronger now than when he left the Demon Slayer Corps, and he wants to know the difference between him and Yoriichi.

After all, those who awaken their markings are bound to die at the age of twenty-five, and Yoriichi is not far from that death line.

If you don't compare now, you'll never have another chance!

Shugo paused in his grip on the blood cup, then kindly reminded him, "If you're going to challenge Yoriichi Tsugikuni, be prepared to die. You're still a step below him."

The words were spoken very tactfully.

Shugo felt that Yoriichi Tsugikuni, with whom he had fought once, was very likely to have also grasped the state of oneness with heaven and man, which would cause Yoriichi Tsugikuni's fighting power to increase dramatically.

Even Kokushibo, who awakened to the Transparent World, was still dead no matter how much he was.

*

“Mr. Yoriichi.” After Tanji returned from selling charcoal, he found the red-haired man who was temporarily staying at his house.

Tanji: "This is your letter. Someone asked me to bring it to you."

Yoriichi was puzzled. Who sent him the letter? After opening the letter, his usually calm expression changed for the first time.

After putting the letter away, Yoriichi said to Tanjiro, "I have to go out for a while, Tanjiro."

Tanji smiled sheepishly and bid farewell to Mr. Yoriichi.