The Butterfly Mansion was established

"All right, this Hashira Meeting has three purposes. First, to formally announce that Kanzaki Kumo will inherit the title of Rumble Hashira. Second, to redraw the territories guarded by the three Hashira. Third, to freely exchange insights on training or information about demons."

Kagaya Ubuyashiki only began speaking slowly after the three had finished their exchange. By now, a hideous purple mark resembling several bulging, intersecting blood vessels was clearly visible on the left side of his forehead.

"It seems Gyomei and Shinjuro have both acknowledged Kanzaki Kumo as a Hashira, so let us go inside to discuss the remaining two matters."

They followed Kagaya inside, where the sisters Hinaki and Nichika, along with Amane, had already spread a map across a large table. Simple symbols divided the map into two territories, patrolled and guarded by Gyomei and Shinjuro respectively.

Kanzaki Kumo glanced at it, considered briefly, then said, "I'll guard the Medical Department and the surrounding area."

"First, this area lies along the boundary between the territories Mr. Gyomei and Senior Shinjuro are responsible for, so I can ease some of the pressure on both of you. Second, the Butterfly Family, whom I just brought into the Demon Slayer Corps, are also at the Medical Department. I'm relatively familiar with them, and having me there will put them more at ease."

In truth, Kanzaki Kumo had long since decided which territory he wanted to guard after becoming a Hashira. His brief consideration had merely been spent thinking of reasonable justifications.

"Besides that, I propose renaming the Medical Department the 'Butterfly Mansion.' It could give the Butterfly Family a stronger sense of belonging. I've personally experienced Butterfly Zemu's medical skills. I suffered a minor injury in an accident while pursuing Lower Rank Three, and the wound contained that demon's poison. It took him very little time to identify it and prepare an antidote."

"I believe a doctor of that caliber is worth some extra effort on our Demon Slayer Corps' part to retain. As it happens, the Medical Department's two doctors are already so old that their hands shake when dispensing medicine. It's time we let them enjoy their remaining years in peace."

"If Mr. Butterfly's medical skills are truly as young Kanzaki says, I agree with this proposal. A good doctor can give the swordsmen fighting on the front lines greater peace of mind when battling demons, and can also reduce unnecessary losses."

"Amitabha. I have no objections either."

"In that case, let us settle on that," Kagaya Ubuyashiki gave the final decision. From that moment on, the Demon Slayer Corps' Medical Department was officially renamed the Butterfly Mansion. As for asking the two elderly doctors for their opinions? They had been trained by the Ubuyashiki Family in the first place. With Kagaya, the family head, having spoken, what objections could they have?

"As for the specific territory Kanzaki Kumo will guard, given how fast you can run, we will assign you a relatively larger area. Would you have any objections?" As Kagaya Ubuyashiki spoke, he marked out Kanzaki Kumo's territory on the map.

Though he called it relatively larger, it was only slightly bigger than the territories Gyomei and Shinjuro were responsible for after Kanzaki Kumo took over part of their burden.

"I have no problem with that."

"Then we come to the final matter: exchanging insights on practicing Breathing Styles, as well as information about demons."

The exchange of information was mainly necessary because routine missions did not require Corps members to submit detailed reports. Usually, the Kasugai Crows and Kakushi merely compiled brief summaries, which could leave out details about demons' behavior or abilities.

Ordinary demons were relatively less important, but this time, Kanzaki Kumo had slain a Lower Rank of the Twelve Kizuki. They still needed detailed information about demons of that level.

"Lower Rank Three had three main characteristics. First, it was very fast. It survived my First Form, and when fleeing, it matched my running speed even when I pushed my Breathing Style to its limit. In the end, I only killed it by relying on a new move I created myself."

"Second, it could create doubles convincing enough to pass for the real thing and draw attention. I only avoided being fooled because of my eyes' special properties. Third, it could conjure throwing darts out of thin air. Its throwing technique was very accurate, and the darts carried a paralyzing poison."

"Because I had to save someone at the time, a dart grazed my shoulder when I forced my way through to kill it. The area around the wound quickly went numb."

"It seems fortunate that you were the one who encountered this Lower Rank Three. If even you, a Thunder Breathing user, couldn't catch up with it quickly, Gyomei and I might very well have let it escape," Shinjuro said seriously.

He had once worked alongside Jigoro Kuwajima, so he naturally knew how much speed mastery of Thunder Breathing granted. Since Kanzaki Kumo had become a Hashira and could kill a Lower Rank single-handedly with almost no injuries, there was no reason to doubt his proficiency in his Breathing Style. That showed just how fast this demon had been.

Fortunately, the demon had already been killed. Speed of that caliber was probably uncommon even among the Lower Ranks.

As for the Upper Ranks, the Demon Slayer Corps currently had no information about them. For hundreds of years, almost no one had returned alive after encountering an Upper Rank.

Kanzaki Kumo did know about the Upper Ranks, but first, he had no suitable justification for revealing it, and second, telling the Demon Slayer Corps in its current state would be useless. Only the brother and sister who held the position of Upper Rank Six could potentially be killed by any two or all three of those present working together.

However, since even Lower Rank Five was not on Spider Mountain, who knew whether the current Upper Rank Six was already in the Yoshiwara Pleasure District? Those siblings changed their hiding place from time to time, and Yoshiwara was not the only pleasure district in the world.

When Shinjuro emerged from his thoughts about the information on Lower Rank Three, he began turning his attention to another matter.

"You said you created a new Thunder Breathing Sword Form?"

"Yes. I sought instruction in Water Breathing from Senior Sakonji Urokodaki and combined two of its Sword Forms with Thunder Breathing's Sword Forms to develop a new form. I named it 'Seventh Form: Dragon's Roam.'"

"What a genius. You've practiced Breathing Styles for such a short time, yet not only have you mastered Thunder Breathing to such a profound degree, you can even create your own Sword Forms. It seems I really am getting old..." Shinjuro's words sounded wistful, but there was no trace of dejection on his face. Instead, he looked at Kanzaki Kumo with appreciation and a hint of fighting spirit.

"You're in your prime, Senior Rengoku. How could you call yourself old? Besides, I may visit your home in a few days to seek instruction in Flame Breathing and see whether I can find inspiration for developing Sword Forms." Kanzaki Kumo took the opportunity to voice his desire to learn Flame Breathing.

The Rengoku Family had always served as retainers to the Ubuyashiki Family, and Flame Breathing had always been passed down through their family. Although other Demon Slayer Corps swordsmen also practiced Flame Breathing, the title of Flame Hashira had always been inherited by members of the Rengoku Family, generation after generation.

Whenever a Flame Hashira retired or fell in battle, the next generation would soon mature and take up the title.

Besides learning Flame Breathing, Kanzaki Kumo also wanted to visit Shinjuro's home to see the still-young Kyojuro Rengoku, as well as Shinjuro's wife, Ruka Rengoku. In the original story, her early death from illness had left the once-cheerful Shinjuro unable to recover. He had even resigned as Flame Hashira and become a washed-up middle-aged man who drank all day.

It was still early now. Perhaps there was still a chance to cure her.

"No problem. You're welcome anytime. It'll also be a good opportunity to show that boy of mine what a true genius looks like."

"Since the Rengoku Family has passed down the title of Flame Hashira for generations, I'm sure your child must be very talented too."

"Compared to you, his little bit of talent hardly amounts to anything." Shinjuro waved a hand, seemingly unwilling to continue discussing his child.