Chapter 6: Demon Slayer

“…Huuuu.”

After returning to reality for the first time in a long while, I felt an awkward sensation for a moment, as if not a single second had passed in this world. But I soon disregarded it. After all, good things are good.

‘I’ll put off worrying about reality for later. For now, let’s focus more on the playful world.’

If there were systems like point-based mechanics or gacha pulls in my playful life, I might have come out frequently to pull some gachas or check my status. But since I could only take with me the skills I had trained in, there was no need for me to come out often.

In fact, it was better to stay immersed in the playful world and focus on my training. Going out too often would only disrupt my flow.

However, now I had no choice but to leave.

This was because the technique I wanted to learn was not in the One Piece world, but rather in another world.

[Breath of Total Concentration]

The technique I needed was the Breath of Total Concentration from Demon Slayer. One thing I had realized during my time in the playful world was that powers that did not fit the world’s rules couldn’t be used, or they would be weakened or altered to fit the world’s framework.

For example, if a world with psychic abilities were to bring that power into the One Piece world, it wouldn’t be usable as-is. It would change, like gaining a Devil Fruit power, to fit within the world’s rules.

Simply put, one can only use powers that align with the world’s framework. So, learning powers from worlds like Demon Slayer, which didn’t quite fit One Piece, would have been useless.

But the principle behind the Breath of Total Concentration was merely increasing the heart rate, so it should be usable in the One Piece world.

While One Piece also had powers like Beast Eating, it wasn’t something I could learn immediately, so I felt that a technique from another world, something I could learn directly, was the best choice for now. And among them, I thought the Breath of Total Concentration was a skill that would be usable in the One Piece world.

With that in mind, I opened the app and checked the ten worlds I could travel to.

[1. One Piece]
[2. Night Run]
[3. My Hero Academia]
[4. Katekyo Hitman Reborn]
[5. Jujutsu Kaisen]
[6. Is It Wrong to Try to Pick Up Girls in a Dungeon?]
[7. Demon Slayer]
[8. Magical Girl Lyrical Nanoha]
[9. Type Moon]
[10. Prisma☆Illya]

7. Demon Slayer. This time, I’ll go there.

[Choose your Playable Avatar]

[1. Kamado Nezuko]
– The protagonist’s younger sister with high compatibility as a demon.
Traits: Sun Resistance, Demon Transformation.

[2. Kocho Kanae]
– The older sister of Kocho Shinobu and a former Pillar. A beauty who excels in everything.
Traits: All-rounder, Flower Affinity.

[3. Kanroji Mitsuri]
– A lovely girl with pink hair and immense physical strength.
Traits: Superhuman Strength.

[4. Kocho Shinobu]
– A current Pillar, skilled in poison-making and medicine, and a beautiful woman.
Traits: Apothecary, Poison Specialist, Doctor.

“Hmm… which avatar should I inhabit?”

‘Maybe I should go with Kocho Shinobu, who has the traits of an apothecary and poison specialist?’

I pondered, then opened my laptop to check the character stories on sites like Namu Wiki.

“Kocho family…”
‘They were a family of apothecaries and doctors, right?’

Then, I found out that Kocho Kanae, Shinobu’s older sister, had also been active as an apothecary and doctor… Perhaps her all-around talent included those skills as well? When I thought of this, Kanae seemed like a clear upgrade, so I chose her without hesitation.

“Starting with Kocho Kanae. At the age of seven!”

I said and began my adventure in the playful world.

“Kanae-nee.”

“Yes? What is it, Shinobu?”

“How can you be so good at everything??”

“Hehe, you can do it too if you put in the effort, Shinobu.”

As I spoke, I patted my younger sister’s head, reminiscing about the past. It had been three years since I entered the Demon Slayer world. During those three years, I had not encountered any demons. Instead, I had focused on studying the Kocho family’s knowledge of medicine, acupuncture, herbalism, and various forms of exercise.

Though I had built up my skills as Boa Hancock, I had never been able to practice them in a professional setting. With my natural talent as Boa Hancock, combined with my all-around abilities, I absorbed everything the Kocho family had to offer, and now I had even reached the point where I could conduct my own research.

In other words, there was nothing more for me to learn from the Kocho family, and now I wanted to learn the Breath of Total Concentration…

‘But, it’s better to leave the Kocho family’s tragic fate behind and emphasize the positive aspects, rather than seeing the family perish like in the original story.’

I thought to myself as I patted Shinobu’s head, who had grown close to me over the past three years.

Although my father and mother were extremely strict, Shinobu had become someone I couldn’t help but care for. I didn’t want to leave her with the same tragic fate she had in the original story. Even if this was just a game, I wanted a happy ending.

Thinking this, I glanced toward the front gate, feeling an ominous premonition…

“…It feels ominous today…”

“Nee-nee??”

As I muttered, sensing the scent of blood, Shinobu, sensing something was off, clung to me.

I gently moved her back, saying, “Stay behind me, Shinobu.”

Though my physical abilities had diminished somewhat with the world change, they were still impressive enough to handle this situation.

That night, under the full moon, the front gate opened, releasing the unmistakable stench of blood.

And within it, the bloodshot eyes of a demon…

“Kick… kick… kick… kkk… delicious─smell…”

“…Sister!! It’s… it’s a monster!!!”

“Don’t worry, Shinobu. I’ll take care of it.”

In the original story, she might have hidden and survived, but that method was unnecessary now. The opponent was nothing more than an unnamed, low-level demon with no remarkable traits. Even though it didn’t have a curse mark, I could deal with it easily.

I took out my small sword, which I had brought with me, and prepared for battle.

Though I hadn’t yet learned swordsmanship, my natural abilities as Boa Hancock, combined with the training I had done here, were enough for me to wield the sword reasonably well.

The demon, having foolishly charged at me, would meet only the cold blade.

“Come at me.”

I said as I gripped the sword firmly.