There are a few hundred members of the Demon Slayer Corps. The organization isn't officially recognized by the government. But it has existed since days of old and still hunts demons today. However, the identity of the leader of the Demon Corps... is shrouded in mystery.

Demons. Staple food: Human. They kill humans and eat them. It is unclear when or where the first appeared. They have impressive physical abilities and their wounds heal quickly. They can reconnect severed flesh and grow new limbs. Some demons can change form. Others possess strange powers. The only ways to kill them are by exposing them to sunlight or by cutting off their heads with a special sword.

The demon slayer corps fight demons face to face. They are human so their wounds heal slowly and lost limbs do not return. Nonetheless, they fight demons in order to protect ordinary people.

"You might be the first exception to this, Y/n." Urokodaki kept explaining to you and Tanjiro. "I am a trainer. Just like it sounds, I train swordsmen. There are many trainers in different places, they use various training methods. In order to joint the demon slayer corps, you must survive the final selection at Mount Fujikasane. I decide whether you may attempt final selection."

You are seen jumping down and up the mountain.

Starting today, Tanjiro decided to write a journal for Nezuko. I told him it was stupid but then he beat me in a battle, so now I'm forced to write my own. Today we have to desend the mountain again, this tiresome training is hard, but it's to make sure we don't die during the final selection.

You are seen leaping over traps down your path. You leap in the air to see a log coming at you and clocks you in the chin and sends you flying back.

I go to up and down the mountain to avoid the traps but Urokodaki is doing something to my path. I swear sometimes there are new traps on my path. My nose and hearing is shaper than ever, but...

You dodge what seems to be knifes by dodging behind a tree. Once your behind the tree, a log comes flying at you again which forces you to duck before running again. You saw a pit of knifes and leaped over it only to get hit by a log again. "GAHHHH!!!!"

He's trying to kill me! I swear he's trying to kill me because I'm part demon! Speaking of which, I have no idea how to use my demon abilities. I guess all I've got is an extra pair of ears, which are basically dog ears, and a more flexible body. I'll see how this will help me, but do I even have any demon energy to draw out?

You land on the ground and grip the ground. You spit out some blood in your mouth and push yourself off the ground.

Today, Urokodaki let me bring Tessaiga with me down the mountain, I quickly learned that it didn't do much to help me.

"TAKE THIS!!!" You shouted and sliced a log, only for three more to hit your body and knock you back to the ground.

I think I'm growing a hatred for logs now. Once I get down my side of the mountain, I have to swing my sword due to Urokodaki's instructions. Urokodaki goes from one side of the mountain where Tanjiro is, to my side all the way across. For an old man, he's very skilled. I have to swing my sword until it's second nature. The first thing he taught me was that a katana will break easily, lengthwise is fine but it can't handle force from the side. When you swing a Katana, you must attack straight ahead. The direction of the blade and the direction of the force you apply must be exactly the same.

"Huh...?" You said as he slammed his fist on top your head.

I didn't get it at first, but I told Urokodaki not to worry about my katana. I have a feeling it doesn't break. We did run into a problem though...

"You can't use my forms." He said to you as you were shocked.

"EEEEEEEH?!" You shouted in confusion.

We discovered that my small demon instinct in my body doesn't allow me to keep a calm mind and fluent strikes like what's required for his breathing style and breathing forms. I was devastated. I basically came all that way for nothing. Although Urokodaki said he was going to help me still with the basics, he said there wasn't much he could do. I have a feeling he was okay with that. Instead, I'll just have to beat him with something else. Hone in what I already know I can do and make it better.

"RAAAAAH!!!" You shouted at him charging at him with Tessaiga. He dodged the overhead strike as he tried kicking you back. You span the Tessaiga, stopping his kick, but the force still sent you back. Before you could strike again, he sweep kicked you and your back collided with the ground, Hard.

That was the plan, but the old man is strong. It feels like every time I get closer, it's like he goes away and gets stronger. I'm telling you, between him and the logs, he hits way harder. Me and Tanjiro only see each other when we get back to the house and then we head to our sides of the mountain. Now... is the six month mark. Nezuko...why haven't you woke up? Urokodaki called a doctor to look at you... but he found nothing wrong. It's strange for you to sleep like this and I could see the look of fear on Tanjiro's face. I'm sure... I don't like admitting this but... I was scared out of my right mind. It freaked me out thinking about what I would do if I found you dead in the morning. I can't help but feeling that, every day and every night.

And so, keeping that fear in my heart, I go higher and higher on the mountain for my training. The thinner air and the dangerous landscape almost prepare me for everything. I thought I would die every time I went higher and higher. A year later, I tried to find myself. To review my life and maybe find something that could help me, my mind only gives me glimpses and flashes of a well. I couldn't figure out what the significance was to me but it didn't help me at all. One day, Urokodaki led me to an open area.

"If you can knock me down, with me going all out. I will approve you for the Final Selection." He said with his katana. You were shaking and scared.

"No...No! He has years of experience! I won't be able to knock him down!!" You thought as he started to walk away. "UROKODAKI!! WAIT!! UROKODAKI!!!"

"When you think you're ready, get me and we'll see." He said and disappeared in the mist.

And so, I would double down on the basics in what Urokodaki could teach me. Flexibility, breathing, and the basic of basics. Making it second nature was hard, but still...

"GAAAAAAAAHHHH-!!!!" You shouted as your beaten up body collided with the frown as Urokodaki shook his head at you before walking away.

"Not ready." That's all he would say every time.

Even a half year later, I can't beat him! I need more! I need to do something! I can't let you die like this!!

"DAMN IT!!!!" You shouted and punched the ground over and over again. "I CAN'T DO IT! GOD DAMN IT!!!!

"What are whining about, you big baby?!"

A man who looked like you suddenly appeared from the mist with a real sword. "W-What the-?! Where's did you come from?!"

"Is that all you've got?" He said cutting you off from asking more questions.

"W-What...?" You were confused as he suddenly made it behind you.

"If you don't do this, you will die." He said as you quickly turned around and pulled out the Tessaiga. He quickly blocked it with his katana but then you put more force on it and the Tessaiga transformed. "I see, smart, but you're not strong enough!"

The man headbutts you and you stumbled back. "Gah-!"

"You've done nothing but whine and complain this whole time! You haven't mastered anything!" He shouted at you and slammed you on the ground.

"That..! That's not true!!!" You shouted as you gripped your sword and charged at him.

"Even your moves are predictable! You definitely haven't learned the techniques Urokodaki taught you! Total Concentration Breathing!" He said and slammed his katana on the Tessaiga. You pushed it back with your sword and went for two overhead strikes, you got one in, but as you flipped your body to do the second one, he sliced you in the back. "NOT GOOD ENOUGH!!"

"GAH—-!!!" Your air was cut as you leaped back as you felt the blood dripping down your leg.

"You just know the facts about the technique, your body doesn't know a god damn thing about using it!!" He shouted and charged at you with a deadly, low slice, you quickly blocked it but shoving the Tessaiga in the ground. The man took the opportunity to twist his body all the way around and hit you back with a wave of energy from his sword.

"GAAAAAAAAHHH—!!!" You felt blood come out of your mouth as you collided with the tree.

"You need to beat it into your body or ELSE YOU'LL DIE!! IS THAT WHAT YOU WANT?!" He shouted at you, holding his blade firmly.

"NO! I don't care about myself!" You shouted and used the tree you crashed into as a boost and used the momentum to spin in a circular motion, spinning your sword vertically. "NO MATTER WHAT! NEZUKO AND TANJIRO COME FIRST!!"

"YOU LITTLE-!" The man span the opposite way the you were to nullify the spinning effect of your attack. You stopped mid way in the air before the man quickly leapt in the air and slammed you to the ground with his hilt. "HOW DO YOU EXPECT TO SAVE ANYONE IF YOU CAN'T SAVE YOURSELF?!"

"HOW DO YOU EXPECT ME TO DO THAT!? HUH?!" You picked yourself up and staggered a bit. "I CAN'T LEARN HIS BREATHING STYLE!! I CAN'T DO ANYTHING!!!"

"THEN JUST MAKE ONE!!" He shouted at you as you were shocked. But he suddenly zoomed to you and unleashed a deadly barrage of attacks at your body, you could barely block all of them. "YOU'VE ADAPTED BEFORE AND MOVED FORWARD WHEN YOU COULDN'T DO SOMETHING! DO IT AGAIN! AGAIN!! AGAIN!!"

"RAAAAAAAAAAAAAAAHHHHHH!!!!!" You shouted to strike again but the man hit his hilt of his sword straight into your chest and you stopped moving and fell on the ground. Knocked out, the man looked down at the Tessaiga.

"Take care of him, old friend." He said as you soon woke up, not seeing the man anywhere. You slowly got up and looked at your injuries.

"Gah-! Tttttttsk! It's amazing-! That I'm not dead...!" You said as you them thought back to what the man said.

And so, I'm writing to tell you, that I'm now making my own breathing style. But making one from scratch is harder than I thought. I'm not sure what training I should do to make it work.

You are seen going all around the mountain avoiding all the traps with your eyes closed. You were trying to keep your breathing constant but couldn't get it quite down.

I decided on trying to harness my demon energy and heighten my senses to the limit. To do this, I go around the entire mountain 5 or 6 times to work on all my senses and train them and my instincts to the max. I could feel myself getting stronger and felt myself unlocking more of my demon energy and drawing out. Because one day...

"..." You closed your eyes and held Tessaiga, red aura flowed around your body as it suddenly went away when you open your eyes and sliced a tree. "RAAAAAAH!!!!"

The trees behind it were destroyed by small wave of concentrated demon energy coming out of your sword. You smiled and shouted. "YESSSS!!! FINALLY!!!!"

And so, I created Demon or Demonic Breathing. I learned to transfer my blood into demon energy as I didn't save much demon energy due to me being less than a quarter demon. This will at least at bring me to the level of a pure blood demon. But I learned that my demon side is underneath, I first discovering it when I was trying to use my forms. I lost control and started destroying everything around me. I think it's because my blood and demon energy goes past what I can handle, or at least I can't overuse the higher techniques I created.

Writing this a couple days later, To be honest, I haven't gone demon mode when using the higher up forms now, I'm starting to think it's tied to my emotions, which sounds really cliché when writing this. Nevertheless today, I incorporated the breathing style that Urokodaki taught me, the smart old geezer made me a formidable force. Basically humans used this to become as strong as demons, so imagine what happens when a demon uses it. Even then, I knew that it wasn't training unless I pushed myself to the brink. And still...

"Come on!!" The man shouted as your blocked his attacks quicker and quickly before you thrusted your sword at him, which barely misses him and he collided his elbow into your face which sent you back. "Better but you're not ready."

I still couldn't beat the man, I couldn't figure out why he looked like me or why he was helping me. Whenever I asked him, he would tell me he was just watching over. I didn't know what but I could careless, and so, I harnesses and mastered my breathing style to the best of my ability. After another six months, I was ready. When I went to face the man, he already has his sword out and didn't say anything.

"I can't afford to waste anymore time. I will win!" You gripped the Tessaiga and he took out his sword.

"Then come at me!" He shouted as you charged at him, you started with a sweep kicked which he leaped over. You knew this and down your body while raising your foot, he saw this and blocked, but the force of your spin kick sent him back. You sprinted at him as he blocked the strike and tried to hit you from the other side. You instinctively raised your sword over your right side of your face, you slid your sword down his before you headbutt him and sliced at him diagonally. The robe he was wearing got cut as he stumbled back as you continued to run at him.

"I can't give him any time to think!" You thought and threw your sword at him. He, obviously, deflected it but you punched the ground, which lifted a part of the ground behind the man, letting the sword come back to you but the man didn't know this just yet. The man tried slicing at you, right to left diagonally and then the opposite but you used your demon heightened instincts and senses to dodge the blades and block one with your arm. The blade went in as you pushed him back before you sweep kicked him with fast motion and momentum from the dodging.

"I see, he used the momentum from dodging to increase the speed and perform spin attacks faster..!" The man thought as you leaped in the air. The sword finally came back in your hand as you span up in the air, gathering your demon energy as your blade turned yellow. You aimed it at the man who was starting to fall to the ground.

"Demonic Breathing 1st Form: KENATSU!!!" You shouted and slashed at the man as a yellow wave of demonic energy went at him. Without you needing to touch the man, the man fell onto the ground, taking the full force of that attack. You landed on the ground and waited for the dust to clear. "HAHAHA!! YES!!"

You saw the man on the ground smiling at you. "Good job, kid... see you next time..."

I was so busy with celebrating that I didn't even realize what had happened. I used my demon energy with my attacks which means my demon breathing forms work. Not only that, I knocked him down. But then... it happened. The man slowly disappeared and in his place....

"U...Urokodaki...?" You said as you saw him on the ground, he looked at you in disbelief.

"You and that boy..." He said as he started to get up. "You actually knocked me down. I wanted at least one of you to survive, so I trained myself when I was away. To grow stronger so you couldn't be able to beat me."

You looked in shock and dropped your sword. He approached you and hugged you. "But you managed to beat me, even as I went all out. You hardly gave me any time to fight back. You... are a wonderful demon, and a wonderful child."

I don't know what it was... maybe it was the fact that I've been training myself to embrace my demon side or the fact that I didn't know I was a demon until two years ago. But I couldn't help but cry...

You hugged him back and he patted your head. "Go to the Final Selection with Tanjiro, and come back alive. Nezuko and I will be here waiting."

After I washed by hair and cut it a bit, Urokodaki gave me a mask. It's was a Fox mask, apparently it's a warding mask that offers protection from evil. If your reading this, it means that we've left without you, Nez. I know you're gonna be mad at me, and I intend to make it back alive to hear your lecture. As of writing this, you are still sleeping, so me and Tanjiro are leaving you in Urokodaki's care and I'm leaving this journal here for you... in case you wake up by the time I get back. This is Y/n. I love-I'll be back with Tanjiro! That's what I meant to say! God, why can't I erase this part!?

"We're on our way, Urokodaki!!" You shouted with a smile and wore Urokodaki's style robe. Even though you couldn't use his style, he still taught you, and you wanted to honor that.

"Give my best to Sabito and Makono!!" Tanjiro's bites as you both left and made your way to the Final Selection.
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"We're finally on our way to the final selection! Aren't you excited?" Tanjiro asked and you smiled.

"Definitely, I get to show off all I've learned and new my breathing style!" You shouted with a smile as Tanjiro tilted his head.

"Is it really forms if the swords doing all the work?" "WHAT DID YOU SAY?!" You got in Tanjiro's face as Tanjiro got a little worried.

"Oh, no, it's nothing. Now, for a Taisho Whispered Rumor: I hear the author gets really easily persuaded by his friends. He's training to become more hardened while also trying to save Royal's rocks. Star's gotta a lotta work to do!" Tanjiro said. "See you next time!"

"Get ready to watch me beat this whole test!!!" You shouted as it faded to black.