Both start in hell: but their talents are multiplied a hundredfold.

When Shen Jue and Butterfly Ninja left the laboratory, it was already half a month later.

The wisteria flower toxin in Shinobu's body has been completely converted into super swordsman serum by Shen Jue.

With Shen Jue's further assistance, Shinobu Kocho successfully mastered the Power Breathing technique.

He even cultivated a black membrane of Armament Haki.

This is thanks to Shen Jue's meticulous teaching day and night.

When the two returned to the Butterfly Mansion, all the people they had met before, including the Stone Pillar, were present.

Besides the Flame Pillar and the other two, the Sound Pillar Tengen Uzui and the Love Pillar Mitsuri Kanroji also arrived at the Butterfly Mansion.

The two twin girls from the Ubuyashiki family also came to the Butterfly Mansion.

The reason why so many Pillars were summoned to the Butterfly Mansion was naturally because of the Breathing Technique of Power and the Super Swordsman Serum that Shen Jue claimed could greatly enhance physical strength.

The already imposing Stone Pillar, Gyomei of Meru Island, has now swelled even more, resembling a small giant.

This truly innately powerful man, who could hold a man-eating demon down and grind it on the ground all night without ever learning a breathing technique, is the only one among the many Pillars who have mastered the breathing techniques of power to successfully cultivate Armament Haki with his formidable physique.

In Shen Jue's view, the next person who might successfully master the Breathing Technique of Power should be Mitsuri Kanroji, the Love Pillar, who has eight times the muscle density of an ordinary person.

"Shen Jue," the two twin girls from the Ubuyashiki family said respectfully to Shen Jue, "has the secret treasure you spoke of been completed?"

Shen Jue wrapped his arms around Shinobu Kocho, who was clinging to him. Although Shinobu Kocho used to appear very gentle, she actually had a cunning and fiery personality. Now, she was like a gentle and domestic woman.

This made it difficult for the pillars present to break down.

"Of course," Shen Jue said gently with a smile, "How could I possibly let you down?"

Shen Jue took out a large amount of sealed super soldier serum from his pocket and said, "You can just inject it directly, but there will be some pain and side effects."

"The Super Swordsman Serum will amplify the user's obsessions and emotions."

"The dosage and duration of each person's use of the Super Soldier Serum are related to their physical strength and willpower."

"The stronger one's physique and the more powerful one's willpower, the more pronounced the effects of the Super Swordsman Serum will be."

Shen Jue patted Shinobu Kocho's head and said, "Shinobu Kocho-sensei, could you please demonstrate the effects of using the Super Soldier Serum?"

Shinobu Kocho smiled sweetly and nodded in agreement.

The petite Shinobu Kocho's gentle demeanor has been replaced by a fierce one. Her still slender body and cute face possess a ferocity that is unmatched by ordinary people.

In the courtyard of the Butterfly Mansion, Shinobu Kocho easily lifted the artificial mountain, which Shen Jue had once played with and which weighed several tons, with both hands.

This incredibly impactful scene left the pillars present stunned in place.

Shinobu Kocho, who was once the smallest of the Hashira, had such weak arm strength that she even developed a variant of Flower Breathing: Insect Breathing.

Shinobu Kocho, the Insect Pillar who usually uses wisteria flower poison to kill man-eating demons, now possesses a physique as powerful as the Stone Pillar.

How could this not shock the many pillars?!

"Then please give it a try," Shen Jue said with a smile. "I will help you cultivate the Breath of Power."

"At the same time, please bring a large number of talented swordsmen who have a deep hatred for demons. I will guide them one by one in practicing the Breath of Power."

"I really want to see that interesting scene when those cannibals encounter swordsmen who have mastered the Breath of Power."

Out of trust in his master and the Insect Pillar Shinobu Kocho, the Flame Pillar was the first to receive the Super Soldier Serum and inject it into his body.

The intense pain caused Flame Pillar to break out in a cold sweat, but his desire to kill the cannibal and protect the people only grew stronger!

When the pain subsided, the Flame Pillar's Demon Slayer Corps uniform was soaked with sweat.

"I've never felt so good before," Flame Pillar said, his eyes brimming with joy. "My physique has increased by at least a third!"

For a powerful swordsman, mastering one's own physique and condition is an essential skill for every Demon Slayer Corps swordsman.

Flame Pillar burst into hearty laughter.

Next, the Pillars tried out the effects of the Super Swordsman Serum one by one.

Among them, the Love Pillar and the Rock Pillar experienced the greatest increase in physical strength.

Super Swordsman Serum doesn't have any drug resistance. As long as the user has enough talent and willpower, Super Swordsman Serum can help them enhance their physique almost without limit.

Recalling Shinobu's crazy appearance after her physique became extremely strong, even Shen Jue felt some phantom pain in his waist after half a month.

It's impossible to complain about being tired, Shen Jue thought to herself.

To Shen Jue's surprise, the two twin girls from the Ubuyashiki family also planned to follow him in practicing the Power Breathing Technique.

The members of the Ubuyashiki family, due to the thousand-year curse of Muzan Kibutsuji, have become so weak that they cannot even reach the basic physical strength required to practice breathing techniques.

But Shen Jue's Super Swordsman Serum gave these two lolis hope.

Perhaps these two little girls are even thinking of using their father's Super Swordsman Serum as a testing ground? Shen Jue thought to himself, but remained silent.

The following days were uneventful yet fulfilling. With Shen Jue's help, the Pillars, who had consumed large amounts of Super Swordsman Serum, all switched to the Breathing of Power technique and developed Armament Haki.

The one who has made the most progress is the Stone Pillar, who has the strongest talent and an incredibly strong will.

The Stone Pillar's physique is now so strong that even rifle bullets cannot penetrate his muscles, only damaging his skin.

After covering his fists with Armament Haki, he can even destroy a multi-story building with a single punch.

Even the Rock Pillar, whose strength far exceeded the comprehension of many swordsmen, still trembled when facing Shen Jue.

Just how strong is Shen Jue? Among the Pillars present, perhaps only Shinobu Kocho knows how formidable Shen Jue is.

The physical foundations of many of the Demon Slayer Corps Pillars have improved significantly. As time goes by, more and more Demon Slayer Corps swordsmen arrive at the Butterfly Mansion and practice Power Breathing under Shen Jue's guidance.

Shen Jue also got to meet the main trio: Kamado Tanjiro, Agatsuma Zenitsu, and Hashibira Inosuke.

During this period, the three main characters had formed a formal team and begun their lives as swordsmen of the Demon Slayer Corps.

Shen Jue didn't care much about which stage the Demon Slayer storyline had reached, because his appearance would definitely cause a huge change in the Demon Slayer storyline.

Gradually, more and more swordsmen came to the Butterfly Mansion to practice the Breathing Technique and take the Super Swordsman Serum.

In order to keep the Demon Slayer Corps running, the swordsmen had to take turns training at the Butterfly Mansion.

This led to the location coordinates of the Butterfly House being exposed.

One night, just as Shen Jue finished making the Super Swordsman Serum, he smelled the scent of cannibals.

A large number of cannibals surrounded the Butterfly Mansion.

Shen Jue revealed a genuinely gentle smile.