Zenitsu wasn't idle either. As soon as Tanjiro cut the webs, he attacked with perfect timing.
"Thunder Breathing, First Form: Thunderclap and Flash!"
SWOOSH!
"Kugh!"
Zenitsu aimed for Rui's neck, but Rui hurriedly tried to dodge sideways. However, the timing was so perfect that, although he avoided a fatal blow, his shoulder was deeply cut.
"You bastards! Not content with harming my family, you dare wound me! I'll kill you all!!"
Suddenly, Rui's hands turned red as he thrust them forward. His webs also turned red, enveloping Tanjiro and the others. Inosuke desperately tried to slash the webs with his twin swords, but they bounced off uselessly.
"Damn it! Muscle Bro! They won't cut!"
"Let me try! Muscle Breathing, First Form: Muscular Flash!!"
CRACKLE!
Tanjiro took a stance, focused his strength into his body, and swung his sword horizontally at high speed. The webs weren't cut—they were torn apart.
"As expected of Muscle Bro!"
I found it a bit odd that Inosuke called Tanjiro 'Muscle Bro', but I decided to figure that out later. Tanjiro's sword, however, was cracked, chipped, and on the verge of breaking.
"Oh no... I'm sorry, Haganezuka (Hotaru)-san."
Tanjiro had no choice but to sheathe the cracked sword on his back and draw the sword he had received from his father. Then he said to Zenitsu, "I'll clear a path. You finish it."
"Got it."
Inosuke also stepped forward. "I can't lose either."
Rui scowled and brought his hands together. Red threads began to spin in a circle around him.
"This is the end. Blood Demon Art: Scattered Threads Circular Slash!"
Rui thrust his hands forward, and the gathered threads shot out, tearing through the surroundings.
CRAAAAAACK~!!!
"Water Breathing, Fourth Form: Striking Tide!"
"Beast Breathing, Fourth Fang: Slice and Dice!"
Seeing Tanjiro use Water Breathing as soon as he changed swords, it seemed he hadn't completely abandoned it. They deflected the incoming webs, creating an opening.
"Now! Zenitsu!"
"Shii~! Thunderclap and Flash: God Speed!!!"
SWOOOOOSH!!!
"Guh!!"
Zenitsu approached Rui at a speed surpassing Thunderclap and Flash, drew his sword, and slashed his neck.
"Th-This can't be..."
Rui, unable to react to Zenitsu's speed, had his neck severed and his body began to burn away. I quickly approached Rui's body, took a syringe from my pocket, stabbed it into his heart, and rapidly extracted his blood.
"Hoo... That was close..."
"Oh, Teacher!"
Tanjiro seemed very happy to see me.
"Long time no see, Tanjiro."
"Long time no see."
This guy had trained his muscles so hard that he looked similar in build to Tengen, though he was shorter. In terms of pure strength, he might even be stronger than Tengen.
'Really, maybe I shouldn't have modified his body...'
After finishing our greeting, while I sealed the blood, Tanjiro placed his hand on Rui's back and looked at him with sad eyes. Shinobu said to Tanjiro, "Showing mercy to a demon is not a good thing, Muscle General."
"To release the grudges of those who were killed, to prevent further victims, of course I will swing my sword at a demon's neck. But I believe it's right to mourn someone who is suffering as a demon and regretting their own actions. They were once human too."
"Hmm... I see. But showing sympathy to demons might get you into serious trouble someday. You should be careful."
Certainly, Shinobu, due to her sister Kanae's death, held a deep grudge against demons. So I could understand her warning to Tanjiro.
Anyway, as the conversation ended, the Demon Slayer Corps 'Silver' units came up the mountain, rescued and treated the wounded, and moved the bodies of the deceased. Unlike the original, Tanjiro and Zenitsu weren't seriously injured, so they received simple treatment, but Inosuke had several broken bones and was wrapped in bandages.
"Damn! Why just me..."
Just then, a Kasugai Crow flew overhead and said to us, "Message! Message! A message has come from headquarters! By the Master's order, all Hashira and the Sword Saint are to gather at headquarters for a Hashira meeting! Caw~!"
Hearing this, Shinobu grumbled slightly, "We just got here, and now we have to go back to headquarters. I haven't rested at all today."
Shinobu left the treatment and evacuation of the wounded to Kanao and prepared to return to headquarters.
"Let's go back, Sword Saint."
"Alright."
As we traveled, I took out some Pringles and ate them. Shinobu, also peckish, kept glancing at them, so I shared some.
"Wow~ This is delicious. As expected, the Sword Saint is also an amazing cook."
I hadn't made them—I'd bought them in the Marvel world—but I didn't mention that.
After traveling for a while, we arrived at the headquarters. The sun was already up, so we ate a simple meal, bathed, and then went to our rooms to rest until the Hashira meeting.
I was sleeping when I was woken by a commotion outside. I went out and saw the Hashira gathered, either lightly sparring or relaxing in the courtyard.
"Long time no see, everyone."
"Sword Saint, long time no see. So you were here."
Obanai greeted me warmly. Normally, he was one of the rudest, along with Sanemi, but since he had enjoyed training at the clinic, he greeted me well.
"Wow~ Sword Saint, it's been a long time~"
Mitsuri also greeted me.
"Yeah, long time no see."
I exchanged greetings with the various Hashira and sat down on the porch. I called Gyomei over.
"You haven't been tormenting your body again, have you? Let me see."
"Sword Saint, I now train while giving my body ample rest."
I examined Gyomei's joints and muscles. He no longer seemed to be overworking his body as before.
"Hmm... You look fine. No problems."
"That's a relief. I thought I was going to be scolded again."
Sanemi looked at Gyomei incredulously. "To see the great Gyomei cower. What a sight."
"And you? Have you toned down your personality?"
"I'll handle it myself, so mind your own business."
Seeing Sanemi being standoffish, I laughed.
"Hah! You're still the same."
Just then, Shinobu, having rested, also came out.
"Everyone was here. Sword Saint, did you sleep?"
"Yeah, I slept a bit."
Then Sanemi asked Shinobu about the Mount Natagumo incident.
"There were some casualties at Mount Natagumo, but I heard a Lower Moon was captured by rank-and-file members?"
"Yes. There are some promising members."
"That's a relief. I was worried the quality of new members was dropping."
We chatted with the Hashira for a while, then the twin sisters came out and announced, "The Master has arrived."
As before, when Kagaya appeared, everyone knelt on one knee and bowed their heads. I remained seated on the porch.
"Thank you for coming, my beloved children. Today, we have several pieces of good news. First, the Sword Saint here has captured Upper Moon One."
At that, everyone looked at me in surprise. Then Muichiro and Tengen spoke.
"Well, if it's the Sword Saint, that's only to be expected..."
"Flamboyant, Sword Saint!"
Kagaya continued, "And as some of you may have already heard, a Lower Moon was captured by rank-and-file members. I am delighted to see so many talented young people. Lastly, there is research underway on a drug that can turn demons back into humans. I cannot guarantee it yet, but if completed, it may become a means to definitively reduce the number of demons."
The Hashira seemed quite surprised. Then Shinobu said to Kagaya, "Master, I also have extensive knowledge of pharmacology. I wish to contribute to the research. With my participation, I believe we can complete it faster."
Kagaya looked at me, seeking my consent. I nodded slightly.
"Certainly, with Shinobu's participation, the research will progress faster. Do as you wish."
"Thank you, Master."
I decided to tell them one more thing. Since so much had changed from the original, knowing this might help them survive.
"May I say something?"
At my words, Kagaya gave his permission. "Please do, Sword Saint."
"I fought Muzan two years ago."
"Th-That's true?"
Not only the Hashira, but even Kagaya seemed very surprised.
"Yes. But he used strange abilities, so I couldn't capture him. I'm telling you this to inform you of Muzan's abilities. You might encounter him at any time."
The Hashira murmured among themselves. Then Kagaya said to me, "Even the Sword Saint could not capture Muzan... But it is fortunate. We can learn more about him."
"There were several reasons I lost him. I didn't even know he was Muzan at the time—it was our first meeting. I only realized because he was different from other demons. The funny thing is, that guy, at the slightest disadvantage, immediately thinks of running away. From his behavior, his top priority is his own survival, no matter what the cost. That's part of why I couldn't catch him."
I explained Muzan in detail: his Blood Demon Art shockwave, his blood-based attack 'Black Blood Extremities', his many tentacle attacks, his body transformation, and so on.
The Hashira and Kagaya listened with intense concentration.
"Then Muzan can change into many different forms?"
"Yes. He could become a woman, or a child."
"I see..."
"And there's another problem. He infuses his attacks with large amounts of his own blood, so if you're hit, you could become a demon or die. Given his tendencies, if he feels threatened, he might go to a populated area, create a large number of demons to cause chaos, and then fight or flee."
At that, Kagaya, looking like he had a headache, pressed his brow. "So... Hoo... Today's Hashira meeting will be long. Children, we cannot stay out here. Let's go inside. Sword Saint, would you care to join us?"
Kagaya asked if I would participate in the meeting, but I didn't want to sit through that. I'd rather play board games with Kagaya's children, so I declined.
"No, I've said enough. I don't think I need to attend."
"I see. Understood."
I returned to my room and played board games with the children again. The third daughter, Kanata, and the fourth daughter, Kuina, couldn't join because they were attending to Kagaya, so I spent my time playing card games with the remaining children. The meeting ran incredibly long, past dinner and late into the night. Finally, it ended, and the Hashira came out, ate, and went to their assigned rooms to rest. I was glad I hadn't attended.
The next day, I prepared to leave. The fourth daughter, Kuina, came to me and said, "The Master said he said nothing to Shinobu, so he hopes you will persuade her well."
Kagaya, given his position, seemed to be leaving Shinobu's matter entirely to me.
"Tell him I understand."
"Please travel safely."
As Kuina was about to leave, I called her back and handed her the card games and Monopoly.
"Enjoy playing with your siblings when you have time."
"Thank you, Sword Saint."
The sisters and I finished our preparations and headed to the car. Shinobu was already waiting by the car.
"So the place researching the demon cure is the Sword Saint's clinic. I'm quite surprised."
"Hmm... There's a lot to say about that, but let's get going first."
"Okay."
We first drove to the Butterfly Mansion. For Shinobu to join the research, she needed various materials and equipment.
The Butterfly Mansion was close to the headquarters, so it didn't take long. When we arrived, Tanjiro and Zenitsu were training, and Inosuke was lying in a bed receiving treatment.
"Teacher, you've come."
"Yeah. No injuries?"
"Aside from a few cuts and scrapes, I'm fine."
"I see. That's good. Zenitsu?"
When I asked about Zenitsu's condition, Zenitsu answered, "I'm fine too."
I also briefly examined Inosuke. He had broken ribs and a broken arm.
"Hmm... This one will take some time to heal."
"You're the Sword Saint! They say you're the strongest! Fight me!"
Even in that state, Inosuke jumped out of bed and tried to grab his sword. The young girls watching nearby tried to force him back down.
"Aargh~! Seriously! If you keep this up, we'll tie you down!"
"Hey! Don't interfere!"
Feeling sorry for the girls trying to restrain the raving Inosuke, I grabbed his shoulder and forced him back onto the bed.
"Whoa!"
Inosuke looked very flustered.
"Fight me after you've fully healed."
"Grr..."
Overpowered by my strength, Inosuke said nothing and just lay still in bed.
"Thank you, Sword Saint!"
The girls bowed their heads to me in gratitude.
"It's nothing. Anyway, Tanjiro, let's talk."
"Yes, Teacher."
I went outside with Tanjiro and told him about his family.
"I'm glad everyone is doing well. I hope Hanako recovers soon... Ah, here are some letters."
Tanjiro handed me several letters.
"Okay. I'll give them to your family. By the way, why does that Inosuke call you 'Muscle Bro'?"
"Well, you see, a while ago, when we first met, we sparred once. I won, so he's been calling me that ever since. I told him to stop, but he says he can't until he beats me..."
Probably, they had fought at the Drum Mansion, and after being soundly defeated, Inosuke had started calling Tanjiro that.
"I see. Understood."
While I was talking with Tanjiro, Shinobu finished packing and came outside. So Tanjiro and I helped load her luggage.
"By the way, you seem to be the only doctor at the Butterfly Mansion. Is it okay for you to be away for so long?"
"Don't worry. Most of the injuries the Demon Slayer Corps suffer are cuts or broken bones. Kanao or Aoi can treat them sufficiently. And if it's a poison, I've arranged for a Kasugai Crow to be sent to me immediately, so there's no problem."
"I see. Understood."