The Promised Day

'That was a close one…' I said in my head.

I was happy that I was able to save Kuina. I was lucky that I thought of learning the first form of thunder breathing in case something like that happened.

It's been one hour since the incident. I wanted to keep what happened between the two of us, and she agreed.

There's no reason to worry everyone about what could have happened, so we put this event behind us.

Now that I don't have to worry about this event anymore…I could focus my time on the important things I really want to train in, especially the breathing style I want.

The breathing style I wanted to train myself in was moon breathing, which was created by Michikatsu Tsugikuni/Kokushibo when he was human and further developed when he turned into a demon.

The main reason for wanting to learn this breathing style was because of the sheer number of forms it has. With so many forms, Kokushibo was very versatile in fights, also his quick but powerful attack style matches with my fighting style.

There were three problems I had about this breathing style though...and this first reason was the one that really stumped me.

How does one mimic the properties of the moon into a breathing style?

With all the other breathing styles, there's a sort of reasoning behind them.

With flame breathing, you breathe in air to give oxygen to the fire inside you or your heart in a literal sense, providing you with energy and power.

Thunder breathing is about quickly taking in air and tensing your muscles, attacking your opponents like lighting.

Water breathing is about always keeping a constant breathing pattern that flows with your movement, like a river or a stream.

Stone breathing is about being sturdy, unbreakable, unchanging. You would take a big breath in and hold it as long as you can.

Finally, there is wind breathing. Wind is untameable, wild, free. There's no holding your breath in with this breathing style. You would inhale, do your attack, then exhale, letting it go. You have to attack instantly.

However, with the other branches of breathing, there was nothing I could go off from. I could come up with guesses for a few of them but that's it, I have nothing. This includes moon breathing.

I spent the last two years thinking of ways to mimic the moon in my breathing. I was close to giving up when an idea came to me two months ago.

Back in my old world, after watching Demon Slayer, I started looking up breathing techniques that existed so I can learn them. There was one that caught my eyes…

It was called 'moon breathing' but not the one we know. Apparently, this breathing technique is used to stay calm and promote sleep. To use this technique, you have to inhale through your left nostril and exhale through your right.

It was the only thing I could do, so I tried it. I pushed my finger on my right nostril and inhaled through my left, then pushed my finger on my left nostril and exhaled through my right.

I did this up until now and attempted to do it unconsciously. I also ask my servants-I mean classmates to do the exercise in my sleep too…I've been getting bizarre looks since then but I always get weird looks so I was already used to them.

I'm far from doing this technique unconsciously. Hell, I was barely able to do it consciously, but when using Total Concentration Breathing…

I stand in front of a wooden pole and ready myself.

"Moon Breathing First Form: Dark Moon, Evening Palace." I quickly draw my katana and slash swiftly in a singular horizontal motion in a crescent shape.

*WHOOSH*

My katana easily slashes through the pole. I sheath my sword and stared at the pole.

I watched as the top of the pole slowly drops to the ground…nice~

I smile to myself for succeeding in the experiment, but here come problems number two and three…

Kokushibo was only able to fully develop his breathing style with his blood demon art. Those crescent moons you would see in his attacks were a part of his demon art. Also, several of his forms need the gigantic version of his sword to do.

I don't really need to worry about the big sword part since I could use Haki as a substitute for the big version of the sword. But for the second part…I already have a plan for it.

I pull out something that I was holding on to for today. It was a strange gray fruit that had swirls on it. At the top of the fruit, there was a crescent moon on the top. What I was holding was a devil fruit. (A/N: Picture of it will be in the comments)

I looked up the name of the fruit and it was called the Tsuki Tsuki no Mi. It is a Logia-type Devil Fruit that allows the user to transform into moonlight and even use the properties of the Moon itself. The user could also temporarily make it into nighttime, making the user a moon man.

I'm lucky to find this fruit in the mountains where I was training. I never knew this fruit existed on this island, maybe it exists because I'm here. It was weird how the one thing I need to develop my swordsmanship is right here in my hands. (A/N: It's definitely not because of plot convenience…)

Anyway, it's time to eat this fruit. I wonder if it tastes just as bad as they say in the anime.

I took a bite of the fruit only to grimace at the taste of garbage island in my mouth. It was so bad that tears were forming in my eyes, but I pushed forward and not only ate the part I bit into but the whole devil fruit.

I took no chances with this, eating the whole thing might let me master the fruit quicker than if I just took one bite. Maybe that's why it tasted horrendous.

After finishing, I closed my eyes and willed my hand to turn into moonlight. Opening my eyes, I see that my hand is bright and is also translucent.

I grinned in excitement at the new possibilities this would open, but for now, I need to train.

Walking away from the clearing, I tried to think of a way to persuade Zoro or Sabo to hit me while I'm blindfolded. They would definitely look at me weirdly…

x-X-x

(Six years later)

I stand in front of a boulder twice my size, staring at it with ill intent. Unsheathing my katana, I hold it in front of me taking a deep breath.

"Moon Breathing Third Form: Loathsome Moon, Chains," I swing my katana rapidly in two gigantic crescent slashes, which also form a storm of smaller crescents to spread.

I took a step back and admired the attack…the whole boulder was destroyed while the ground it stood on had deep cuts in it.

Now that's a lot of damage.

"Are you done destroying the place yet?" Said a pleasant but brisk voice.

I turned around and found Kuina behind me.

She grew tall during the years, she's currently 5'10 (177.8 cm). She's wearing an outfit that goes well with her looks. (A/N: I picked two outfits that I like, I want to see if you all like them too. If you have other outfits that would look good with her then don't be afraid to put some in the comments.)

"Come on! Sabo and I are finished with packing everything, go get dressed so we can leave." She said, smiling at me.

"Alright alright, I'm going to get dressed! Wait for me at the beach." I playfully said jogging back to my room.

I trained a lot over the years…I mastered Total Concentration Breathing and Total Concentration: Constant.

Three years ago I got Koushirou to get specially made gourds to test on. I broke through the first one but didn't succeed on the next one. One year later, I was able to break all of them.

I also trained in some of the Rokushiki, mainly Soru and Geppo. I tried to learn Rankyaku, but there was something else I was missing to use it for battle.

I couldn't learn the other ones because I already had so many things on my plate…

Like…for example, Haki. It took a full year of getting beaten by a stick to finally grasp Kenbunshoku Haki. I was able to complete the initial training and the next thing I did was wear a blindfold at all times for two years.

It took some getting used to, but I was handling it. It helped me with training, that's for sure…

Busoshoku Haki was a bit difficult because of my young body, it took a while for me to get it to work but I did it. Though, at present, I still need to work on it some more. How I got it to work was pretty ingenious of me actually, it happened several months ago.

When using Kenbunshoku Haki, I'm able to feel my surroundings and the presence of other living things. After my two years of being blindfolded, I'm able to sense intent and some emotions.

Busoshoku Haki is basically willing your spirit to a part of your body with the intent of hardening it. So, I would lower my Kenbunshoku Haki tightly around my body to get a sense of intent.

This way of training not only helps with my Kenbunshoku Haki but also my Busoshoku Haki!

Now…my devil fruit ability has been working wonders with my moon breathing as you saw earlier, but I don't only use my devil fruit with my moon breathing…I came up with some moves~

But that's for later, I already made it to my room.

Going inside, I take a look at myself in the mirror and observe, I grew taller...my new height is around 6'2 (187.96 cm). My hair looks wild and the back of it is tied up in a ponytail. (Kind of like Kokushibo's but only stopping around his neck)

All the baby fat around my cheeks was gone and my chin was pointed, making me dangerously handsome. I took out the clothes I prepared for my debut and put them on. (A/N: What he's wearing is in the comments)

I went outside and prepared myself to go to the beach.

'Soru' I instantly disappeared.

After a few seconds, I made it to the beach. Everyone that I cared for is waiting there to see us off. I'm taking Sabo and Kuina with me on this journey, Zoro is staying back since I want him to be in Luffy's crew. He was pissy about it though…

"Are you ready, Noah?" Kuina questions with a beaming smile.

I smile back, envisioning all the exhilarating things that are beyond this water.

"Yes, I am."