----------(3rd POV: Hayate)----------
"Run, Hayate! Don't stop until you collapse, you hear!"
"Easy... for... you... to... say... lazy old man!"
Hayate received a knock on his head for his troubles, like usual. The boy was currently running from the top of the mountain to the bottom and back while carrying Jigoro on his shoulders. He was told by his dear master that this would be the first step to learning "how to breathe correctly," as he put it.
It had been a month since Jigoro had revealed the existence of demons, and Hayate had done nothing but run, run, and run some more.
When the old man had told him that he'd be first helping him expand his lungs, this wasn't what he thought was going to happen. He had done similar things when he was first taken in, and now he was just repeating the process again, much to his chagrin. To think that this mystical way to breathe would require him to do the same thing he did back then, just more intense, was enlightening, to say the least.
His training continued until sunset. He was exhausted and could barely move and yet... he felt fulfilled. Even though he complained and whined half of the time while doing it, he couldn't help but feel good, feel accomplished. His master's words only increased that feeling.
"Good job, brat. I know you're disappointed at how monotonous and simple this is, but it's the only way to move forward. This running has helped you in increasing your stamina, and the heavy air up on the mountaintop has made you more efficient when breathing."
Hayate smiled at the praise and couldn't help but make fun of the old man a bit.
"Yeah, you sound real wise, master. I'm sure this was all for my sake and not for your own twisted amusement. No way."
Jigoro glared at his disciple halfheartedly before letting out a snort.
"You're lucky that you're tired from training, brat! You better pray to whatever god you believe in for mercy, because when the sun rises tomorrow, I'll show you what true hell looks like." He finished with a manic grin on his face.
The boy, in that moment, realized that the man training him was a devil, and so he entered the perfect dogeza pose and asked for mercy.
"Please have mercy on me, oh wise master. You know I didn't mean anything by it, right?"
"Isn't this familiar? Seems you're gonna go your entire life bowing to me with your head buried in the ground. Sadly, no matter what you do, you are going to suffer come morning."
"You're joking, master, right? Right? Masteeerrr, pleeeaasse don't do this to meeee~"
Jigoro ignored his disciple's wailing as he exited the room, not even sparing him a glance.
Hayate's body went numb, and he did as his master recommended.
'Please God. Save me and help me survive tomorrow. I want to at least live long enough to try and accomplish our deal!'
Little did he know, not even God would save him.
----------(Switch)----------
"Total Concentration Breathing. The original technique used by demon slayers to enhance their physical abilities through the use of breathing. You need to breathe deeply and allow the air to spread across your entire body in order to strengthen your muscles."
Hayate sat on the ground in a lotus pose, meditating and focusing on his master's words. He took a deep breath and tried to hold it in for a bit before releasing and attempting to do it again, only to end up coughing heavily and choking on the very air he was trying to breathe.
"Damn brat! That's wrong! Why are you so impatient?! It isn't that hard to fucking breathe, is it?"
"Easy for you to say, old man! This shit's harder than it looks!"
"The hell?! Where did you learn that word?!"
"Oh, I don't know, use your infinite wisdom to figure it out, master."
Thunk!
"Respect your elders, you damn brat!"
Hayate grumbled quietly as he rubbed the bulge that was starting to form atop his head. He let the tension in his muscles go and fell unceremoniously to the ground.
He just felt so frustrated. He'd been at this since the moment he woke up and yet he still couldn't do it after hours and hours. Was it really that hard? Isn't he supposed to have a body tailored to this?
Jigoro stared at his apprentice's angry expression and sighed. The boy was doing much better than he thought. If it were that easy to learn Total Concentration Breathing, then it wouldn't be a fundamental skill of the corps. His problem was obvious.
Seems it was time for him to get into his teacher persona.
"Alright brat. Stand up and follow me, let's try and get you some inspiration."
"Master...?"
The boy stood up and followed his master as they climbed the now far too familiar mountain.
"I don't think climbing the mountain will help much, master."
"Be patient. You'll understand when we get there."
The pair continued their trek for the next half hour until Jigoro suddenly stopped and turned around to face his disciple.
"You have enhanced eyesight, don't you? Look over the horizon, what do you see?"
Despite his doubts, Hayate turned around and what he saw made him freeze.
He could see it. All of it.
The mountain was relatively bare compared to others, so his line of sight was clear. He could see the village at the foot of the mountain. Their small house. Some animals running around in the valley below. The river that ran close to the village. He could see the people and their smiles.
It was beautiful.
"You didn't answer, what do you see, Hayate?"
Hayate remained entranced and replied automatically.
"Well, there's a couple of animals running around in the valley. I can see old man Yotsuba selling some udon. There's..."
"That's not what I meant. Focus and tell me what YOU see. Not what's objectively there."
He processed the words before hesitating slightly and finally responding.
"Peace. It's so peaceful, master. It's as if demons don't exist. As if no problems exist. There's no fear or panic, nothing. Just... joy, I guess."
"You called the sight beautiful before. Do you still think so?"
"I... Yeah. I think I do," he replied with a beaming smile.
Jigoro nodded his head before allowing a smile to bloom on his face.
"Well done. You've done it."
"Huh?"
It was only now that Hayate realized how much stronger he felt. It was like the difference between night and day, as if chains that were trapping him were now destroyed.
"But how..."
"Why do you think I brought you up here?"
Hayate shook his head to get rid of the shock before glancing at this master and replying.
"I don't really know, master."
"It was so you can relax."
His eyes widened as it finally clicked.
"The reason you were failing beforehand is that you were too tense. You needed to relax and calm down. Total Concentration Breathing isn't something you should force yourself to do. You don't force yourself to breathe, you just simply do it. It's the same thing. This breathing technique is something you should learn to do unconsciously.
Sigh... Sit down, Hayate. This old man is about to go on a small rant, so unless you want to just stand there awkwardly..."
Hayate plumped down onto the ground without hesitation and gave his full attention to his master.
Jigoro chuckled at that before continuing.
"Hayate, you have a distinct advantage over others. That advantage is your age. Most demon slayers don't learn what I just taught you. They simply learn Total Concentration Breathing for the sake of using swordsmanship and stop there. That is wrong, but trainers like myself or others are forced to teach them that way because most of those that come to us are holding a grudge and are too impatient to learn properly. So, we teach them swordsmanship and train their reflexes without guiding them in the proper way to breathe, the one that draws out the power of the human body.
You, on the other hand, I will teach properly. I will first teach you to breathe, then I will train you in swordsmanship, and only at the end will I teach you the unique style which I know. By doing this, I'm making sure that you're as prepared as possible when you eventually become a demon slayer yourself."
They stayed quiet for a few seconds before Hayate adopted the dogeza pose he had gotten used to. Only this time, it was genuine.
"Thank you so much, master. For everything. I will make sure to live up to your expectations."
"I appreciate your words, Hayate, but there's an issue within them."
Hayate lifted his head and stared into his master's compassionate eyes. Jigoro was looking at him like a grandfather would a child. This wasn't the first time he had sent him such a look, but it was never this... deliberate.
"Child, I don't want your entire life to be dedicated to living up to my expectations. You've been putting unwarranted pressure on yourself and now I understand why. You're just a kid, Hayate. You feel a sense of responsibility towards your training and I understand, but you are only hurting yourself. These people you saw down there, the peaceful scenery. That's what we fight for, but it shouldn't be at the cost of your own peace. Relax, let everything out and simply... breathe."
"Master... I..."
"What did I just tell you? Don't talk, only breathe."
The boy closed his eyes and took a deep breath before letting it out. He did so again and again for what felt like hours before he finally reached a limit and winced as he felt his lungs sting. Yet, despite all the pain he was feeling...
"How do you feel?"
"Free. I feel free, master. I'm... relaxed. No, I'm happy."
The two smiled at each other as the sun set over the horizon, illuminating their figures.
{A/N: A special chapter here. The only one excluded from the rules I put in the INTRO chapter. Honestly, I did it to satisfy my mild OCD, since I would like it better if we went from chapter 5 to 15 to 25, etc., rather than 14 to 24. I'm personally proud of this chapter, and I feel I did a good job at adding a bit of lore to Demon Slayer and showcasing the relationship between Hayate and Jigoro. I always found it weird that Urokodaki never taught Tanjiro Total Concentration Breathing Constant, so I came up with that explanation for it. I hope it makes sense.
Now I'll do something I never thought I would do and ask anyone who's willing to give the book some power stones. I usually don't care much, but I want to see how far I can take this. So if you enjoyed this chapter, please make a small donation. Thanks a lot, and see ya'll in the next batch of chapters.}