Chapter 198 198: 198 Demon Slayer 4

Sanemi, perhaps very angry, swung his sword wildly. I effortlessly parried his strikes with my dagger.

Clang! Clang! Clang!

"Hmm... A fierce sword."

Sanemi, sensing something was wrong as he swung, gradually took on a flustered expression.

"You're an amusing rookie. I can sense you hesitating behind your anger. You'll never make it with that lack of emotional control."

"Shut up!! Wind Breathing, First Form! Dust Whirlwind Cutter!"

Sanemi raised his sword, spun his body, creating a vortex, and charged at me.

Rat-a-tat-tat!

Thump!

I blocked all of his spinning strikes on the spot and grabbed Sanemi's head. Then I read all of his breathing techniques from his memories.

"Unbelievable…"

The other Hashira seemed very surprised. Seeing their techniques, which even they couldn't easily block, being stopped so simply, they looked quite flustered.

"Argh! Let go of me!"

As I held his head, Sanemi struggled to break free, so I simply let him go.

"I've seen everything I need from you. Let me give you one piece of advice. Don't be ruled by your emotions. Keep your head cool and your heart hot. Remember that."

"Shut up!! Second Form!!"

This guy, even after I gave him advice, couldn't come to his senses and continued trying to attack, so I quickly approached, grabbed his wrist to stop him before he could attack, and stabbed his shoulder with my dagger.

"That's for Nezuko!"

Stab!

I immediately pulled the dagger from his shoulder and slapped Sanemi across the face, back and forth.

"That's for Tanjiro!"

Smack! Smack!

Then, adjusting my strength so as not to kill him, I kicked him in the abdomen, sending him flying far away.

Thump!

"Ugh!"

"And that's for my face."

Sanemi crashed through a wall of the estate and stopped. He didn't move, so he seemed to have been knocked out.

I looked at the other Hashira and said, "Rookies, I hope you'll do your best to entertain me."

At my words, the Hashira broke out in cold sweats and gulped.

"What are you doing? Aren't you coming?"

At my words, Kyojuro Rengoku drew his sword and said, "I am the Flame Hashira, Kyojuro Rengoku. You are truly strong. I wish to learn from you."

Then the other Hashira also drew their swords. Then Mitsuri Kanroji quietly said from the side, "I wanted to say that…"

With those words, the Hashira's combined attack began. This time too, I leisurely blocked them with my dagger, observing and learning each of their techniques and breathing forms. I particularly watched Tomioka Giyu's Water Breathing closely, and I also grabbed his head and read his memories. He got flustered and started acting up, but I was able to learn it all.

Shwoosh! Clang! Clang!

"This is impossible! Our attacks aren't working at all!"

It was only natural. My [Observation Haki] was EX rank, and my agility far surpassed the level of ordinary humans.

Just then, I heard a voice from behind.

"Move aside!!! Eighth Form! Gale Cutting Flash!!"

It was Sanemi attacking. As soon as he regained consciousness, he warned the Hashira who were surrounding and attacking with him, and unleashed a big technique.

CRAAAANG!!

I was not hit, of course. The sparring was temporarily halted by his attack.

"A corpse is moving."

"What!!"

"You know as well as I do that if I had intended to kill you, your head would already be severed."

"Kuh…"

Sanemi, knowing that fact well, couldn't retort and just frowned.

"Well, fine. You still don't seem to acknowledge the difference in our levels, so I'll show you something interesting."

"Wind Breathing, Tenth Form. Tornado."

"What!!!"

Wind Breathing only had nine forms. The Tenth Form did not exist. So Sanemi seemed extremely shocked.

I created the Tenth Form by combining the rotational force of Wind Breathing First Form, the consecutive strikes of Second Form, and the mid-air twisting of Seventh Form, and unleashed it at Sanemi.

SWHAAAK!!!

The strikes were so fast that even though he was cut multiple times, only a single sound was heard, and in an instant, several slash marks were left on Sanemi's chest. Of course, I was careful not to endanger his life.

"Kugh! This is… impossible…"

Thud!

"Sanemi!!!"

At the sight, the other Hashira rushed to Sanemi.

"Don't worry. I cut him enough that he won't die."

Then Kagaya called out, "Let's stop here, Teacher Jin."

"Understood."

I sheathed my dagger and put it back in my pocket. Sanemi received treatment, and the other Hashira had a meal with Nezuko and me. As they ate, they kept glancing at me. Then Shinobu asked me, "Who are you?"

"Didn't I introduce myself earlier? My name is Jin. I'm a doctor."

At that, Shinobu looked utterly dumbfounded.

"What nonsense… There's no way an ordinary doctor could fight the Hashira like that and not even be winded!"

"You speak as if you're someone special, but to me, you only look like frogs in a well."

"W-Well…"

After the meal, with nothing to do in the evening, I was lazing around in my room when suddenly the door opened and Sanemi, wrapped in bandages, came in.

"Hey! How do you know Wind Breathing? And what's this Tenth Form!!?? Who are Nezuko and Tanjiro!!"

At those words, Nezuko looked flustered. I looked at Nezuko and put my finger to my lips, signaling her to keep it a secret.

"Did you forget your manners? Knock and come back in. Or I'll cut off your wrist."

When I said that, Sanemi went back outside and knocked.

Knock, knock, knock!

"Come in."

Bang!

"Damn it! What the hell am I doing…"

"So, you want to know about the Tenth Form?"

"Yeah!"

"I just watched your techniques, combined them, and used them."

Sanemi seemed unable to believe it.

"What!! Are you saying that's possible???"

"Really, you don't believe me. Follow me!"

I got up and went out to the courtyard. Sanemi and Nezuko followed behind. Several Hashira were in the courtyard, but ignoring them, I drew my sword and showed Wind Breathing First Form, Second Form, Seventh Form, and Eighth Form in succession. And with more precision than Sanemi himself.

"Th-This can't be…"

"And this is a technique that combines only the strengths of those techniques."

SWOOOOSH~!!!

"..."

After I stylishly demonstrated the technique, Sanemi just stared, speechless.

"I'm going to rest now, so don't bother me."

As I sheathed my sword and tried to return to my lodgings with Nezuko, Sanemi called out to stop me.

"Wait! Let me ask just one more thing. What did you say that technique's name was?"

"Tenth Form, Tornado."

"I see. But Nezu… no, never mind."

When we returned to the room, Nezuko asked me, "Teacher, are you truly the strongest in the world?"

"Yes. Do you believe me now?"

"Yes…"

Another day passed like that, and the next day, Kagaya, supported by the twin sisters, came to my room.

"I have made my decision. I will teach you all the breathing techniques. But since you are that strong, do you not need breathing techniques and swordsmanship?"

"Collecting swordsmanship is a hobby of mine. Anyway, if you hear any news of Muzan, contact me at the clinic."

"You intend to leave?"

"Yes. There's nothing for me to do here. I'll be at the clinic, treating patients, so send one person who knows a breathing technique each month. Wind Breathing is already done. I've already learned it all."

Kagaya looked very disappointed at my words. He seemed to have hoped I would stay and hunt demons.

"Understood."

Nezuko and I packed our things again and were about to get into the car to return to the clinic. Then Shinobu came and silently got into the car.

"Hmm? Why are you getting in?"

"I'm the first. I'll teach you the Insect Breathing this month."

"I see. Understood."

I drove to the clinic. It took some time because it was a bit of a distance. During the drive, Nezuko and Shinobu were laughing and chatting in the backseat about something fun. They seemed to have become close in the meantime.

When we arrived at the clinic, people crowded around, seeing that I had returned. It seemed that sick people had been waiting for me to come back.

"Oh my, Teacher, you've finally returned."

"My knee hurts so much I think I'm going to die, Teacher!"

"Teacher!"

"Tea…"

"..."

I began treating them quickly. As I prescribed treatments, Nezuko packaged the medicine and handed it to the people. Shinobu also helped alongside her. By evening, aside from two people who needed surgery and were admitted, we had finished.

"There will be surgeries tomorrow, so the two of you must fast from today. If you eat anything, the surgery could go wrong and become dangerous, so please abstain."

"Understood, Teacher."

I tidied up the hospital room a bit and came out. Shinobu and Nezuko were waiting outside.

"You've worked hard, Teacher."

"Yeah. We traveled a long way today, and there were many patients, so you must be tired. Let's rest. And show Shinobu to an empty room."

"Okay."

The next day, I operated on two patients, and while Nezuko helped with their recovery, I saw other patients. Then a third emergency surgery patient came in, so I performed the surgery and finished the consultations. Then Shinobu came to me and asked.

"A patient whose appendix had burst and whose internal organs were contaminated—they would have died. How was it possible to save them?"

In this era, penicillin and various medicines had only recently been introduced from Europe, and surgery success rates were very low. If the appendix burst and the organs were contaminated, the patient simply had to die. Shinobu asked because she wasn't familiar with modern medicine.

"That level of patient can be saved. If you're so curious, learn and take the knowledge with you."

"Understood."

From that day on, after consultations ended, Shinobu also began learning medicine from me. At the same time, I began teaching Nezuko swordsmanship. What I taught Nezuko was Water Breathing. I thought it would be better to start with Water Breathing, which was less strenuous on the body, as Sun Breathing seemed to strain the body too much.

I specially transferred the [Swordsmanship] ability to Nezuko. With my [Teacher] ability at EX, I could now choose a rank one level below the ability to transfer, starting from E-rank. I transferred [Swordsmanship] to Nezuko at A-rank, so her learning was incredibly fast.

That wasn't all. Using [Haki Infusion], I increased Nezuko's physical density considerably. This was possible because I had observed the body of Kanroji Mitsuri, who had a unique constitution, with my [Naked Eye] while fighting the Hashira. Instead, as a side effect, her appetite increased.

As the clinic became busier, I hired two smart young nurses from the city to help me and Nezuko. Of course, I read their memories beforehand to ensure they were trustworthy. Shinobu also helped me, assisted in surgeries, and learned various medical knowledge.

On a day off, I asked Shinobu to show me her swordsmanship. Since that was the purpose of her coming, Shinobu agreed and demonstrated behind the clinic.

"Are you sure it's okay after just one demonstration?"

"Yes. I've learned it all now."

At that, Shinobu was very impressed.

"You are truly a genius."

"Hmm... But most of your attacks are thrusts. Give me your sword."

"Yes, here you go."

At my words, Shinobu handed over her Nichirin Blade without suspicion.

SNAP!

I immediately applied force and broke Shinobu's sword. Shinobu, very flustered, said to me, "What are you doing!!"

"This sword is garbage. I'll make you a new one."

"Eh???"

At those words, Shinobu looked dumbfounded this time.

Anyway, a week later, I made her a new thrust-oriented Nichirin Blade, similar to her previous one, but not a bladeless sword—I gave it an edge and made it much stronger. While I was at it, I also made surgical tools from alloy and packed them in a leather bag.

"This is…"

"It's your new sword. And I also made you some durable surgical tools."

"Thank you."

Shinobu, delighted with the surgical tools I gave her, then picked up the new sword and swung it a few times.

"Huh? I thought it would be heavier than my old sword because it has an edge, but it's not."

"Yeah. And I changed the back of the hilt so you can fill it with poison. If you ever encounter a strong demon, I'm sure some will be immune to poison. So there may come a time when you have no choice but to use the blade. That's why I kept the edge. Give me the sword again."

This time, after some hesitation, she handed it over.

"You're not going to break it again, are you?"

"I'm not going to break it. I'm going to show you a demonstration."

I immediately took the sword, assumed a stance, and showed her a modified form of Insect Breathing I had researched and created over the week.

"Thrusts are still the main focus, but with modifications like this, you can also cut. You can also use it irregularly. Instead, it will require some practice."

"Oh~ I see."

I decided to also teach Shinobu about the state of mastery in swordsmanship.

"Listen carefully, Shinobu. There is a stage that all swordsmen must pass through. If you don't reach it, you can't even be called a swordsman."

"What is that?"

"The Transparent World."

"The Transparent World?"

"The Transparent World is a state you can reach when your swordsmanship has reached a certain level and all unnecessary things have been stripped away. You can perceive all sensations of yourself and your opponent."

"I see. So by your standards, I'm not at a level where I can be called a swordsman."

"By my standards, that's where it begins."

At that, Shinobu sighed.

"I thought there were few swordsmen stronger than myself, but hearing you say that makes me feel infinitely shabby."

"Do you know why I'm telling you this?"

When I asked, Shinobu thought for a moment and then said, "Hmm... I'm not sure? 'Strive harder'?"

"No. I'm saying you should give up one of the two. If you learn medicine while your swordsmanship is still half-baked, you'll die before long."

"But Nezuko…"

Shinobu compared herself to Nezuko.

"Nezuko has almost finished learning medicine. Besides, she's only learning swordsmanship to protect herself. And above all, as my assistant and student, she's always under my protection. Your situation, fighting demons, is different."

"I-I see."