"Leave me alone!"
"NO! FIGHT ME!"
Sanemi could recall all the times he's been annoyed in his two lives. He's been pretty annoyed at Giyuu's antics, and he remembers many times with Tanjiro. If we were to sum up all the frustration that he experienced in all those moments, he doubts it'll cover even half of what he's feeling right now.
As Inosuke continues following him, Sanemi recalls his time after the war. After the war there was no where to express his anger towards. The source of his hatred has finally been eradicated and as such, Sanemi found himself no longer waking up with hate. Of course he still experienced hate, mostly towards himself, but in all honestly it was a minuscule amount.
They say that revenge doesn't help the heart but Sanemi begs to differ. His revenge towards the demons have been enacted and his hatred soon left him. He found himself smiling from time to time and he was no longer quick to anger.
Even now when he went back in time, he found himself remain mostly calm. After all, he already aid in the eradication of demons, so even though he was back in time he didn't find any anger within in. To top it all, being in the past served as a way to correct his mistakes and in turn remove the rest of the anger he has on himself.
However when it comes to this kid with a boar head, Sanemi couldn't help it but give in. Sanemi turns and punches him, sending Inosuke stumbling back.
"SHUT THE HELL UP! GET THE HELL OUT OF HERE!"
Inosuke just laid down, his lungs struggling to regain oxygen after that strike. However soon, he starts laughing. Then he launches himself upwards on his feet and points his thumbs towards himself.
"Hahahaha! Again! Do it again! You won't be able to knock me out! I am the king of the mountain!"
Sanemi just screamed in frustration...
At some point Sanemi just gave up and let Inosuke follow him. Inosuke of course had a lot of questions, but Sanemi wasn't planning to answer them. Unfortunately, that didn't stop Inosuke from continuously bombarding him with more questions.
"Who are you?! How are you so strong?! What was that thing you killed?! Why do you breathe like me?! Could you fight me?! What does that thing say on your back?! Where can I get your swords?!"
Sanemi was honestly having none of it. However suddenly he realized something and stopped in his tracks, making Inosuke also stop and tense in anticipation for a fight.
"Oi brat... what did you just say?"
"Where can I get your swords?!"
"No before that."
"What does that thing say on your back?!"
"No I mean before that."
"Could you fight me?!"
"NO! I MEAN... *sigh*... I mean before that. That thing about breathing."
"Why do you breathe like me?!"
Sanemi just stares at Inosuke. Part of him is in shock. The other is in disbelief.
"You're saying that you are breathing similar to me?"
"No! I'm saying YOU are breathing similar to ME!"
"... and you made this breathing by yourself?"
"Of course! For the Great Mountain King Inosuke Hashibira, making my own breathing is easy!"
'There's no way...'
Sanemi has come to meet many prodigies in his lifetime. Some have been able to utilize the hardest breathing form. Others have managed to become Hashira in two months. And others have stood at the pinnacle of strength while remaining blind.
However Sanemi has never, and I mean NEVER, seen someone create their own style of breathing WITHOUT ANY KNOWLEDGE. Anyone who has created their own breathing has to have derived it from something. Whether it's from a different form, a master, or records; a new form has to always be based from something in the Demon Slayer Corps.
That is because breathing as a weapon isn't something you're born with or learn consciously (with the sole exception of Yoriichi Tsugikuni), but a skill that has to be taught in order to utilize it. For Sanemi, it is simply impossible to learn and create your own breathing style from scratch.
Sanemi closes his eyes, leaving Inosuke confused. After a couple seconds, he reopens them and his grey irises turn red.
"Hey! What happened to your eyes!"
"Shut up."
Sanemi looks at Inosuke's lungs with the Transparent World, only to confirm what he's been hearing. Inosuke is indeed using a breathing form. Not only that, but his breathing form is eerily similar to Wind Breathing. With deviations and modifications detected in the breathing, Sanemi can safely classify his breathing as a branch of Wind Breathing.
But can Sanemi really say that? Sanemi recalls a conversation he had with Shinjuro after the war. When the topic drifted to Tanjiro, Shinjuro explained that his Hinokami Kagura was really Sun Breathing. Sun Breathing was the first breathing form to ever exist and as such, every form takes inspiration and derives from it. Water, Earth, Flame, Wind, and Thunder all derived from it. From there, any other form of breathing dervives from those five. As such, Shinjuro calmly explained that every single form is just a specialized imitation of Sun Breathing, as every form takes inspiration from it.
However if what Inosuke says is true, then what he did was a feat that hasn't been replicated since the first user of Sun Breathing. He has genuinely created a breathing style from scratch and free from the influence of Sun Breathing. Then again, Sanemi can very well see that his breathing still draws inspiration from Wind Breathing, so it's also possible that Inosuke coincidentally derives his breathing from Wind when in creation.
Regardless it was a shocking feat, and even more shocking that it came from Inosuke out of all people (who is currently 12 years old). Sanemi tries to recall anything he knew about the kid from before, but he couldn't conjure up anything. All he remembers is that he helped take down Uppermoon 2, and that he got married to Aoi. How Aoi managed to fall in love with him of all people confuses Sanemi and is way above his pay grade.
Sanemi stares once again at Inosuke. Specifically at the two blue eyes in the boar head. Finally Sanemi lets out a sigh and pinches his brow in frustration as he exits from the Transparent World.
"Look brat. Why don't leave me alone? Don't you have someone to return to?"
"No way! The Great Inosuke Hashibira rules this mountain by himself!"
"No one? No parents?"
"What's a 'parents'?"
Sanemi choked in surprise from that response. 'Damn really?'
"Well I mean a mom? Or a dad? Or a sibling?" continued Sanemi.
"Uhhhhh..." responded Inosuke in confusion. "I don't know about a dad or a sibling, but my mom died a long time ago so I wear her head in honor >:) "
Sanemi looked at the boar head in whole, then at Inosuke's body language. It seemed he was proud that he was able to answer that question. Or any question for that matter.
'God this kid is helpless' thought Sanemi as he groaned internally. But then again, Sanemi can somewhat relate...
After a couple seconds Sanemi came up with a decision.
"Alright brat. Look, if you leave me alone for today and meet at this spot in high noon tomorrow, I'll teach you something. But after that you need to leave me alone!"
"High noon?" Inosuke questioned as he scratched his head. "Is that when the sun is at the highest?"
"Yes. We got a deal?"
"YES! I WILL MEET YOU SOON WHITE-HAIRED CRUSTY LOOKING MAN!" screamed Inosuke as he runs back to his shelter, screaming on the way back. Sanemi just bites his cheek as he fights the urge to chase after him and send him flying.
***
"AHHHHHHH! WHERE IS THAT WHITE-HAIRED MAN!"
It's been a while since noon (an hour to be exact), and Sanemi has yet to meet Inosuke in their designated location, much to Inosuke's frustration.
"AHHHH! SO THAT'S HOW IT IS! HE THINKS HE CAN FOOL ME?!" Inosuke looked up to the sky and screamed, "ME, THE GREAT KING OF THE MOUNTAIN, INOSUKE HASHIBIRA?! THE NEXT TIME I SEE HIM I'M GOING TO DESTROY HIM!!!"
"God don't you ever shut up?"
Inosuke immediately reacted and retreated from the sound. Lo and behold, Sanemi was there, standing with a long object wrapped in cloth.
'Unbelievable! I wasn't even able to sense him! He's fast!' thought Inosuke as he remained in a defensive stance.
"Are you going to just stand there, or are you going to lead me to a clearing so I can teach you something?"
Inosuke growled (to Sanemi's astonishment) before puffing loudly.
"Hah! Very well! Follow me!"
Sanemi just rolled his eyes before following Inosuke as he started walking. In a couple minutes they reached a clearing with no trees and boulders. Sanemi looked around before deciding this should do.
"Alright brat sit down across me" said Sanemi as he puts his package down and sits on the soil with his legs crossed. Inosuke follows suit and sits across him.
"Oh and one more thing," added Sanemi. "Remove your mask,"
"What!" responded Inosuke. "Why should I remove my mask! You can't tell me wh-"
"Oi," interuppted Sanemi as he glares at Inosuke. "I'm not asking. I'm telling. Remove. your. mask."
Inosuke feels a shiver go down his entire body as he looks at Sanemi's harden gaze. After some hesitation, Inosuke follows his survival instincts and removes his mask. As Sanemi thought, he looks almost exactly as he does in the future. A feminine face with blue tips on the end of his hair. The only difference is that his face carries child-like properties.
"Alright listen to me well. I won't tolerate any interruptions. Do you understand?"
Inosuke gulps before nodding his head in response.
"Good. Alright what I'm going to teach you is Total Concentration Breathing."
Inosuke waited for Sanemi to finish before responding, "Total Concentration?"
"Yes. What you are doing is a specialized breathing form unique to you. However it takes effort and I imagine you can't do it all the time. When you try it's very weak isn't it?"
"Yes! I try my special breathing, but when I do it all day it doesn't work well."
"That's because your breathing style is meant to be used in bursts for attack. What you want to be using is Total Concentration for all time use and your specialized breathing form when you're on the attack."
Inosuke stayed quiet in response as he tried to take in what Sanemi was saying, before understanding it and nodding his head.
"Alright let me teach you how to do it. Follow my instructions."
Inosuke straightened his posture in response.
"First close your eyes... take a deep breath in and hold it in... as you hold it in, strengthen your core and you gut. You should feel your lower body strengthening... as you release your breath, you should feel your heart pump fast... you should feel the blood rushing all throughout your body... once you feel that repeat again..."
Sanemi opened his eyes as he activated to Transparent World and see Inosuke's progress.
'Tch. Unbelievable...' As Sanemi stares at Inosuke's lungs and blood vessels, he sees Inosuke perfectly replicating the instructions Sanemi stated. In his first try, Inosuke was performing the Total Concentration Breathing.
'Then again, the brat already had a breathing form. Perhaps it comes natural because he already mastered his breathing.'
Regardless it was an incredible feat that only solidified the theory that Inosuke was a prodigy.
"Alright stop. How do you feel?"
Inosuke returned to his normal breathing and opened his eyes.
"This was... amazing! I could feel my strength go all in my body! My arms were a little weaker but my legs were very powerful!" Inosuke shot a grin as he looked at his hands and squeezed them.
"That's good" replied Sanemi. "Knowing Total Concentration is a crucial step to becoming a Demon Slayer"
Inosuke looked back up at Sanemi. "Demon Slayer?"
"People like me who eliminate demons like the one you saw me kill. If you enjoy fighting and want to continue living that lifestyle, then becoming a Demon Slayer is the path you need to take."
Inosuke stayed quiet in contemplation as he considered the strength of Sanemi. Sanemi meanwhile took the package to his left and unwrapped it, revealing two Nichirin swords.
"Woah! Those are swords! Where did you get them?! I don't like how they look!"
"You don't need to know where I got them, and I don't care if you don't like how they look" replied Sanemi in frustration.
In truth Sanemi got them from a Wisteria House. There was a Wisteria house nearby this mountain so Sanemi decided to pay a visit early in the morning. Many injured slayers come there to recover. Unfortunately not every one survives and their swords are left unattended in the house. Most people may see that using the weapons of the dead as disrespectful, but Sanemi sees it as a way to utilize their swords to carry on their legacy of slaying demons.
Normally, trainees only get normal katanas. However seeing that Inosuke is alone in the mountain where demons could come, and remembering his fighting style from before, Sanemi thought it would be best to gift two Nichirin katanas.
"Here you go. From now on these katanas belong to you..." said Sanemi as he presents the swords in front of Inosuke.
Inosuke stares in awe at the metal of the blades before reaching for them. However before he could grab them he gets kicked back and launched all the way to a tree. As Inosuke recovers and wipes blood from his mouth, he dizzyingly looks at Sanemi approaching him with the two swords.
"OWW! WHY WOULD YOU DO THAT?!!"
"It's a warning," responds Sanemi in a calm tone as he he crouches to Inosuke's level. There his face turns murderous and his voice deepens.
"These swords are to never be used against humans. If I ever find you using these swords against people, I promise that kick will be the lightest attack you ever felt in your life."
Inosuke inhaled sharply as he feels the sweat pour down his head and his hair stand up. Years in the wild have right now made him realize one thing. Right now he isn't looking at a human, but staring at a apex predator, the pinnacle of strength.
Sanemi stared at Inosuke's petrified face for a couple more seconds before standing up and brushing the dust of his pants.
"Stand up. I promise not to attack you again, unless you give me a reason to."
Inosuke hesitated for a while before slowly standing up. Sanemi handed him the swords and Inosuke reluctantly took it.
"The breathing I taught you? You're going to practice it until you can perform it all day. Even in your sleep."
Inosuke looked up at Sanemi, his fear slowly dissipating.
"You're already physically built and you have a good sense of touch, but you still are going to want to work on your reflexes and enhance your senses. Utilize your sense of touch in your combat. Your greatest advantage it that." continued Sanemi.
"Your breathing form. Does it have a name? Mine is called Wind Breathing" asked Sanemi.
Inosuke hesitated in thought before coming up with a name, "... Beast Breathing... I'll call it Beast Breathing." Inosuke was no longer yelling.
Sanemi nodded in acknowledgement before continuing, "That breathing is for attack. Come up with forms, or different attacks, that uses that breathing and your katanas. This will help you when you come to face a demon."
"You must practice your sword swings. Practice 100 of times until your arms feel sore. Then practice even more till you can't hold it anymore" continued Sanemi.
"Also get used to get hurt. I don't care how you do it. Practice falling. Get hit from animals. Find a way. You need to practice being in pain and learn to continue fighting while in it." added Sanemi.
Inosuke took all this information in his brain without interrupting. Sanemi looked at him, trying to think if he missed anything.
"Alright that's it. Once you feel ready join Final Selection. To find out where it is, look around till you spot someone that has the same or similar cloths as me and ask them. However I forbid you from taking it until 3 years later. Understood?"
Inosuke thought for a bit, then shook his head yes. Sanemi internally sighed in relief. He didn't want to deal with anymore of this boar head.
Normally what Sanemi told Inosuke to do would be suicide. Every trainee needs a trainer or someone to guide them through. Attempting to train by yourself is simply foolish. However something told Sanemi that Inosuke would more than alright.
'Besides, he supposedly done this before.' Sanemi wasn't worried for him at all. He's seen his skills and potential and knows he'll be alright for final selection.
"Alright then brat. I'll be off. You better not follow me" said Sanemi.
Inosuke clenched his jaw. It seemed he wanted to say something, but he didn't know what to say.
Sanemi just scoffed before turning around and saying, "one more lesson-" grabbing Inosuke's attention.
"-when you feel gratitude, you should say 'thank you'. It's common courtesy."
Inosuke's eyes widened before he clenched the swords he received. As he watched Sanemi's figure retreating down the mountain, he finally said something normally,
"T-Thank you..."