Chapter 9: Demon Slayer Corps

As I left the Kochou family and joined the Demon Slayer Corps, following Himejima’s guidance, I learned about the Demon Slayer Corps during our journey.

“First of all, the organization we’re joining is called the Demon Slayer Corps. It’s an unofficial group that deals with the monsters you’ve encountered—the Blood Demons.”

“…Demon Slayer Corps?”

“Yes. Let me explain about the Blood Demons. They are monsters that consume humans and grow stronger from doing so. While they were once human, they are now creatures that cannot be killed by simple means. Even if you sever their head or limbs, they will regenerate almost instantly.”

“Then, how can they be killed?”

Although I already knew the answer, I asked the question. He nodded and showed me the weapon wrapped around him—an axe and a mace connected by a chain.

“This weapon is the key. This is called the Illyundo. It’s made from black crimson ore that absorbs sunlight, and it’s a weapon that contains the power of the sun.”

“A weapon that contains the power of the sun?”

“Yes, the only way to kill a Blood Demon is to expose them to sunlight. If they’re touched by sunlight, they will turn to ash and die. This weapon is imbued with sunlight, so if you cut a Blood Demon’s head with it, you can kill them even at night.”

“…A weapon imbued with the power of the sun… Illyundo…”

“Yes, this is the very weapon that symbolizes the Demon Slayer Corps.”

I nodded in understanding. Indeed, the Illyundo was also a symbol of the Demon Slayer Corps in Demon Slayer.

“But is that all? No matter how I think about it, the Blood Demon is incredibly strong. I was able to fight them, but I don’t think an average person could win just by wielding a weapon.”

“That’s exactly right. It’s extremely difficult for an ordinary person to confront a Blood Demon, no matter how much they train.”

Himejima muttered to himself, sensing a small presence nearby, and swallowed his words.

‘So, you managed all of that, even though you were still so young and hadn’t properly trained? Truly remarkable.’

Swallowing his thoughts, Himejima began explaining another weapon of the Demon Slayer Corps: Total Concentration Breathing.

“But in addition to the Illyundo, the Demon Slayer Corps has another weapon for fighting Blood Demons—Total Concentration Breathing.”

“Total Concentration Breathing?”

“It’s a technique unique to the Demon Slayer Corps that awakens and strengthens the human body, much like the Blood Demons.”

I felt my heart race as I listened, leaning in. This was the very reason I had chosen to enter the world of Demon Slayer. It wasn’t just for the sake of mastering traditional medicine or medical techniques, though that was also part of it.

With these thoughts in mind, I looked at him with eager eyes as he began explaining the basics of Total Concentration Breathing. Afterward, he continued explaining the structure of the Demon Slayer Corps and led me somewhere.

“Where is this…?”

“This is one of the Demon Slayer Corps’ safehouses.”

“A safehouse of the Demon Slayer Corps…”

It must have taken about a week. He led us into a remote mansion in a quiet part of town. As I looked around, I couldn’t help but think, ‘So, the Demon Slayer Corps has safehouses like this.’

Anyway, after entering, he left the many people working inside and immediately retrieved a katana from somewhere, handing it to me.

“…What is this?”

“This is the standard Illyundo.”

“This is the Illyundo…”

“Grip it tightly.”

“Tightly?”

“Yes, when you do, the Illyundo will change its color to match your unique traits.”

Although I already knew the answer, I pretended not to and, feeling excited, gripped the Illyundo. It hummed and began to change color from its usual silver blade to a soft pink—a sight so incredible that I could hardly understand the mechanics behind it.

“Wow…”

“Pink… Hmm…”

“Does this color mean anything?”

“Yes, the color of the Illyundo reflects the type of breathing technique the person is suited for. Yellow signifies Lightning Breathing, and gray like mine signifies Rock Breathing. However, pink is unusual…”

“So, what happens then?”

“In that case, you’ll likely have to create your own breathing technique.”

“Create my own breathing technique?”

“Yes, after learning the basics of breathing, you can modify it to suit yourself and create a new one.”

I nodded thoughtfully at his words. Himejima patted my head, a firm confidence in his touch, as if he trusted me completely. He believed that, despite having to create my own breathing technique, I would succeed.

Given my talents, it was a reasonable belief.

I looked at the pale pink blade and gripped it tightly.

‘Flower Breathing…’

It was the name of the technique used by Kochou Kanae in the original story. It definitely seemed fitting for a technique involving the soft pink blade. While I could easily access the original knowledge by revisiting the original work, I decided against it. I wanted to create my own technique without any preconceived notions.

After all, my talent was far superior to that of the original Kochou Kanae. There was no need to limit myself by adhering to the original techniques.

It was better to come up with something that perfectly matched the flower theme, based on my own imagination.

With that in mind, I decided to think about how to create my own technique.

“To create a new breathing technique, I’ll need to learn the basics first. So, it would be best to start with Water Breathing.”

“Water Breathing?”

“Yes, Fire, Water, Wind, Rock, and Lightning Breathing are the five main techniques. Water Breathing is the most versatile and easy to learn, making it ideal for beginners.”

Himejima began explaining the advantages of Water Breathing. It was a soft style of swordsmanship, well-suited for women, and because it was less restrictive, it was easier to modify and adapt compared to other techniques. He explained all of this to me.

Of course, I nodded along, and when I agreed to learn Water Breathing, Himejima smiled and said he would take me to the best instructor he knew.

“Your talent is exceptional, so I’ll make sure to take you to the best instructor available.”

“Thank you.”

“He’s a former Water Hashira, so he’s the best person to teach you.”

I couldn’t help but widen my eyes at those words. There was only one former Water Hashira that Himejima could be referring to: Urokodaki.

Would this mean I would become the protagonist’s teacher? I thought to myself as we headed to the mountain where Urokodaki resided.

“…Hmm…?”

Swoosh!!

Urokodaki, who had been chopping wood, adjusted his mask and looked toward the mountain base. He sensed a presence quickly approaching.

Despite his age and retirement, Urokodaki was a former Hashira, and he couldn’t miss this presence. As he realized it was human, he stopped chopping wood and put down his axe.

“Looks like we have guests… Given their speed, they must be at least Pillar level.”

‘It’s time for training, then…’

A Pillar-level person seeking an instructor could only mean one thing. Moreover, two presences were approaching, so it seemed likely.

Urokodaki prepared to greet the visitors, and sure enough, two figures appeared from the mountain base—a massive blind man and a small child sitting on his shoulder.

“Hello, Urokodaki.”

“Ah, it’s you, Amjuro. Welcome.”

“Excuse me.”

And so, I began my training under Urokodaki.