Sakonji took the boy to his house, the Demon also climbed into his brother's basket when the sun began to rise. As they ran, Sakonji saw in the distance his home. Arriving there Sakonji wished to test how fit the boy was right away.
"Put your brother in the house and follow me".
Yoriichi placed the basket down inside the house and ran after Sakonji up the mountain. Night falling, Yoriichi arrived at the peak of the mountain, the air was as thin as a reed and the wind was screaming in his ears.
"From here," said Urokudaki, "you will descend the mountain to where my house is at the bottom."
Then he suddenly vanished. That's it? Thought Yoriichi. All he had to do was get to his house by dawn, he thought he could do that, then again most people could*. He dashed down the mountain at blinding speeds, in the distance he saw something, he could not discern what until he got closer. Traps, he thought, of course there are. Dodging and weaving he raced down the mountain, determined to reach the bottom as fast as possible.

Sakonji arrived at his home and in the front door stood a woman, or more accurately a girl. On her shoulder stood one of the Kasugai Crows, Giyu's. How many people was he going to send? He thought. The crow flew towards him with a message, Greeting Sakonji Urokudaki sir. This girl is in the same condition as the boy I sent before, but it seems that they know each other. Please take care of her Urokudaki sir, she reminds me of my sister. Once again I realise that my requests are brash, but I hope you will forgive me for it. Of course I will, he thought, exasperated by the constant requests. Though that was hardly fair, Giyu rarely asked for favours. He was a quiet boy after 'his' death.
"Follow me, girl. Your friend should arrive by sunrise."
"Thank you so much, sir and my name is Uta." she said joyfully.
He entered the home and thankfully the demon boy had yet to emerge from the basket.

Looking at the girl he noted her small stature. Poor girl, he thought, we have true demons in this world and yet we humans still manage to be just as bad.
"Are you hungry?" He asked,
"Yes, I am." Uta replies.
He walked over to his pot where a stew was cooking, he took off the lid and a waft of flavour crashed on his face. He didn't know he got so good at cooking but it didn't matter.
"That smells good!" said Uta, and he agreed.
Just as he opened the pot he heard the door open, looking towards the door he saw Yoriichi.
"I finished, Urokudaki sir." Yoriichi said.
As he looked at Urokudaki he saw Uta. Uta looked overjoyed when she saw him, and also surprised for some reason.
"Yoriichi!"
"Uta, you're here."
Yoriichi was surprised that she was here, he did not know that Giyu did not hear him.
"Yes, a guy named Giyu dropped me off. Did you send him?"
"Yes he did, now both of you eat." Urokudaki wished to see for himself how fast the boy was, this speed was unnatural.

Urokudaki took Yoriichi back up the mountain to see how fast he went. The boy's speed was incredible, he had seen nothing like it before, not only that, he came back unscathed. Reaching the top of the mountain he said,
"Once again you will descend this mountain to the same place."
Once again he disappeared into the mists. Urokudaki had a feeling that Yorichi was perhaps blessed with some otherworldly powers, as his intention was to follow Yoriichi down the mountain, but the moment he disappeared Yoriichi ran off so fast that he almost lost him. Urokudaki dashed down the mountain as fast as he could, Yoriichi was definitely going faster this time. Urokudaki had reached first, the last time, after all. Urokudaki ran down the mountain and saw Yoriichi at the bottom. Nearing the bottom he slowed to a walk, though the boy was fast, there was no sense in showing him that. It would not be good to inflate his ego, though he didn't think the boy had an ego.
"You are quite fast, I will change the course and its length for later, but now I provide insight on what you may become should I allow it. The Demon Slayer Corps number in the hundreds. It is an organisation not acknowledged by the government, however they still exist and kill demons. Demons are flesh-eating, beasts. They have powerful physical abilities, and can heal themselves even when body parts have been removed. There also exist demons who have the ability to alter their body structure. If one does not use a blade made of a special metal, a demon will survive even after cutting off their head. If you want to enter the demon slayer corps you need to survive final selection on Mount Fujikasane."
Urokudaki was prepared to train the boy in the art of the sword, he fast enough and it seemed he listened well enough.
"I am a cultivator of swordsmen, I will train you in the way of the sword."

Over the next few months he trained the boy in the way of the sword, Yoriichi was learning incredibly fast and now that Urokudaki had increased the distance of his mountain obstacle course he now had to run up and down the mountain regularly. He had also given Yoriichi a newer, thicker wooden box for Michikatsu. The boy had superhuman strength and skill, so perhaps it was time to teach him the breathing styles. He was a prodigy, all but mastering Kendo and Kenjutsu styles of swordsmanship. But, Urokudaki had noticed a strange behaviour of the other boy, something that needed to be monitored. Every night he would leave the house and one day Urokudaki saw him leave. He quickly and quietly leapt up and followed the boy out the house. Michikatsu began to run up the mountain, before stopping when he reached a clearing. Urokudaki did not remember the clearing, but he crept up behind a tree anyway and noticed the crescent shaped cuts all over the trees in this area. The boy suddenly drew his sword, and before he could do anything, Urokudaki stepped out. "What do you think you're doing?" he asked not unkindly, he wasn't expecting a response, yet suddenly he spoke.
"I was supposed to become a demon slayer."
Michikatsu had a deep voice that, coupled with his height, made him sound older than he was.
"I was supposed to be the greatest demon slayer, and yet I was made into a demon."
"Yet, you have a sword?"
Urokudaki realised that perhaps Michikatsu was trying to relive his days of training to be a demon slayer.
"It seems that I can still fight demons as a demon. I had my own breathing style when I was training to be a demon slayer, I have been perfecting it in this clearing. I wish to still become more than just a demon."
"Show me your forms, perhaps I could be of help."
Michikatsu said nothing in response, but he was more than willing to oblige. He drew his sword incredibly quickly and Urokudaki watched as he performed his moves, "First Form: Dark Moon, Evening Palace" Michikatsu performed a singular horizontal slash following a crescent shape, creating numerous chaotic crescent blades along its path, before sheathing it back into his scabbard. Urokudaki noted that this technique was extremely reminiscent of Iaijutsu. He began to perform his Forms from the first through to the sixth. Each form was incredible, not only were the techniques themselves quite effective, but they had small crescent like blades following after each strike. "Impressive, that you have developed such powerful techniques."
"There is still one more."
Slowly the boy lifted the sword holding the blade horizontally, with one hand, in front of his neck. Urokudaki finally properly saw the blade for the first time. Its blade is blood-red, with a veiny appearance, and numerous eyes cover the blade and the tsuka (handle). His katana's tsuba (Guard) is circular with four slight indentations, a centre with three eyes and several black veins, and a golden border. He carries it inside a saya (scabbard) at his waist that shares a similar fleshy appearance. but then, suddenly the blade began to transform.

It suddenly grew 3 more smaller blades out of it and increased greatly in size. "Move back"
Urokudaki had to agree, and jumped back.
"Seventh Form: Mirror of Misfortune, Moonlit."
Using his altered katana, Michikatsu performed a frontal crescent-shaped slash that unleashed numerous straight and curved slashes that expand outward. A large section of the trees in this area were torn apart. Now he knew why there was a clearing.
"Such power and destruction."
He was impressed at the power of the attack, and the range was incredible.
"How did you come up with such a strange idea? Of using your sword in such a way."
How powerful was this boy, how much power had Muzan given him.

Michikatsu thought back to his younger years. He used to practise hard everyday and night, until his hands bled and he could no longer swing his sword. He remembered the day he first made the Seventh Form, Six forms in his opinion could hardly constitute a proper breathing style. But when trying to do what he had envisioned it didn't work. It only came out as a strange hybrid of forms one and two, so he had decided that he would need a larger sword. Wandering about, he found a bamboo training sword, and attached half of another training sword to it. Once again he returned back to his training area and began trying to perform the attack. It worked better this time, the range and power though in his opinion it was still lacklustre. He decided to work on his earlier six forms and perfect them before moving on.
"I intend to make many more forms, this is one of many forms."
"You could use some guidance with this endeavour."
Michikatsu realised that it was just Urokudaki trying to keep an eye on him, but he had no qualms with it. Let the old man do as he pleases, he thought, he could use the help anyways.

Michikatsu began training alongside Urokudaki at night, whilst during the day Urokudaki helped Yoriichi train. Michikatsu didn't know how the man did it, nor did he care. Michikatsu standing outside in the same clearing as before, drew his sword. Michikatsu heard something near himself, looking back at the hut, he saw Urokudaki leaving with a bag on his back,
"Where are you going?" he called out, soft so that those within the house could not hear him.
"Do not leave here, I will return at dawn."
Michikatsu nodded and began swinging his sword. He knew he always had room to improve, he had seen how his brother could fight, and although Yoriichi claimed to not like the sword his skill did not lie. Yoriichi was made for the sword, Michikatsu was not. As his late father had so eloquently put it,
"there is room for only one of you."
Although, his father was dead, so what did he know, Michikatsu thought bitterly. Michikatsu had tried to train his body physically, yet it seemed now he was too strong. No matter what he did, it did not feel difficult. So now all he did was practise his swordsmanship and breathing. Suddenly, an image appeared in front of him. A man that seemed familiar, it was the man that killed his family. Then he felt a pain across his entire body, a pain deep in his body. He could feel that demon's gaze on him. Sheathing his sword, he roared in agony. That vile creature was searching for him, and it hurt alot. He turned to see his brother emerge from Urokudaki's home.
"Brother, what's wrong?" Yoriichi called out to him,
but Michikatsu didn't notice, he felt blood spilling from every opening in his body.
"Brother!"
Yoriichi began running towards him. Michikatsu felt his grip on his mind beginning to loosen. Yoriichi came close and Michikatsu was afraid that he might hit Yoriichi, he disliked his brother but not that much, luckily he could no longer stay awake and passed out.

Urokudaki had returned with a book to help train Yoriichi. It contained a breathing style that was far more complex than water breathing. Something Yoriichi could possibly master, it was the origin of all breathing styles. As he entered his home he saw blood covered Michikatsu on the floor as Yoriichi watched over him. Uta was placing a wet cloth on his forehead.
"What happened here?"

"I don't know, he was outside and suddenly he roared much like a tiger and when I went outside he started bleeding."
Yoriichi's usually emotionless demeanour was betrayed by his hunched body, he was clearly distraught.
"Take the cloth off, it will do him no good." he said kindly, she was trying her best after all. This seemed familiar, he had seen it before on a demon, one of the more powerful ones. It seemed to be the work of Muzan, perhaps.
"He should be fine, Uta, you look after him and inform me when he wakes. Yoriichi come with me, we have a lot to do today."

Urokudaki left his house, he could do anything until Michikatsu had woken up.
"Urokudaki sir, what about my brother? What's wrong with him?"
"He will be fine, there is nothing we can do for now. We will have to wait till he wakes." Urokudaki began to take the book from his bag.
"Breathing Styles are swordsmanship styles that make use of an esoteric breathing technique known as Total Concentration Breathing practised and taught by members of the Demon Slayer Corps and are used in combat by Demon Slayer."
Urokudaki informed him as he pulled the book out of his bag. He showed it to Yoriichi, the book itself looked simple but the contents inside were worth the while.
"I will teach you Total concentration breathing, but you must learn the rest."

"What's inside the book?" Yoriichi asked,
"That can wait, first you must understand how to perform Total Concentration Breathing and to perform it constantly. Total Concentration Breathing is a breathing technique which involves expanding one's lungs to intake as much air as possible, accelerating one's blood flow and heartbeat while increasing their inner body temperature, resulting in their bones and muscles becoming more active." Urokudaki explained,
"Do I do it like this?" Yoriichi began to breathe in deeply, Urokudaki could see the clear signs that this was the breathing technique. As Yoriichi exhaled, the air exhaled was visible, his body seemed heightened, elevated in some way.
"You seem to have done this before."
"Yes I have."
"How long can you keep it up?" Urokudaki was impressed, he genuinely didn't understand how much more of a prodigy this boy kept becoming.
"About a few hours." Without training that was quite impressive, but when fighting powerful demons Urokudaki knew a few hours wouldn't cut it.
"We will need to make sure that you can maintain total concentration breathing constantly. It will greatly boost your prowess in battle, increase your physical fitness, and will truly help in mastering this particular Breathing Style." Urokudaki said, whilst pointing at the book.
"For now I will have you run even more, and most importantly rupture these gourds." Urokudaki took out a few gourds, each bigger than the last, the final being about the size of a table**.
"After running up and down the mountain, you will return here and attempt to break a gourd for 30 minutes, then you will once again run up and down the mountain. If you do break the gourd before the 30 minutes is over, you will move on to the next one and repeat the process."
"Yes Urokudaki sir, but if I may ask?" Yoriichi asked inquisitively,
"You may."
"What is wrong with my brother?"
Urokudaki himself wasn't too sure about the answer to that question, but he believed that Yoriichi deserved an answer.
"Before that there are things you must understand about demons. They have a creator, their king, the one who turned your brother into a demon. His name is Muzan Kibutsuji, he has complete control over all demons and though I don't know if this is true, I believe your brother is fighting against the control of Muzan. Unfortunately, there is nothing we can do at this point but wait for Michikatsu to wake and see if he survives."
"Then does-"
Urokudaki interrupted him,
"No further questions, now run." Yoriichi begrudgingly took off on a run up the mountain.

Michikatsu saw that demon once more,
"I cannot see you Kokushibo, how can you hide your presence from me?"
Michikatsu dared not speak, for fear the demon may hear him. Yet, he was no coward, he prided himself on his presence, on his grandeur, on his majesty, and most importantly on his power. How could he cower in the face of this demon a being who willingly gave up his humanity for power, yet just by looking for him, the demon almost tore him to pieces. Plucking up the courage to speak, Michikatsu said,
"Who are you?"
"You dare ask a question of me? Show yourself."
The demon couldn't see him, why? He thought. Perhaps the demon would leave if he tried to hide his presence further. Michikatsu quieted his thoughts and began to focus on his breathing, nothing else.
"Hide from me all you want, I will find you boy."***
Michikatsu suddenly awoke once more. The marks on his face were burning, and although he didn't know at first, he could now see through people. Suddenly someone next to him gave a squeal, Uta. he looked at her with all six of his eyes, and noticed he could see through her body and see her bones, muscles, and blood. Each twitch in her muscles determined her movement, he could see how his brother saw. He immediately realised how weird that was and looked away embarrassed, though he didn't show it. Urokudaki and Yoriichi burst into the room, he could see inside them too, what was happening.
"You're awake?" Yoriichi asked,
Michikatsu did not respond, not to him. For a while they just stood around and watched Michikatsu to see if he did something strange or not. They decided that Michikatsu was safe and Urokudaki spoke once more
"Yoriichi, it seems your brother is fine, you may leave and so may you Uta."
Yoriichi didn't argue and once again begrudgingly complied. Uta on the other hand was happy to leave, she had rarely seen Michikatsu and it didn't get less scary each time she did.

After they left, Urokudaki sat down and spoke,
"What happened?"
"The demon who transformed me, he was looking for me, I could feel his power in my cells. He was tearing me apart, but for some reason he could not see me. Who is he?"
"I will not utter that man's name in front of you, if you know it he will know that you know too. But, I believe you should be fine, if he could not find you now he should not be able to find you for a while. I myself do not know why he could not see you, from what I know he can control every demon, though possibly that excludes you."
"Not only that, but now I see through people, everyone, much like Yoriichi does. I want to perfect it, I want to understand it."
"I would not know how to do that, why do you not ask Yoriichi?"
"No, I do not want to." Urokudaki had noticed the one-sided hate between Michikatsu and Yoriichi. Though Yoriichi loved his brother, the same could not be said for Michikatsu. It was not that Michikatsu hated his brother, but it was something else that Urokudaki had not yet figured out.
"Why?"
"It is nothing I will figure it out, you wouldn't understand." Michikatsu got up and walked into his box. Urokudaki got up, he would have to find a way to help Michikatsu love his brother once more, but he knew that ultimately that decision would lie in Michikatsu not him. He stood outside the door and found Uta cheering Yoriichi on as he ran down the mountain to the gourds. He did not want Yoriichi to go to Final Selection, he had no doubt that Yoriichi could cut the boulder, so he would have to devise a more difficult task.

Thanks for the nice reviews once again, and thanks for the advice Djoklecjan! I hope I understood it properly. Took a while, but I had things going on.
*No they can't, Yoriichi usually assumes that he isn't all that powerful.
**he brought a larger gourd cause he knew that Yoriichi is blessed
***Sound familiar?
****It was some kind of partial selfless state form that he had entered. He himself cannot enter a full selfless state because he has hate, rage and a fighting spirit, but I guess he can enter a partial selfless state now as he isn't as aggressive.

Important - If anyone feels like it I need forms 4, 11, 13 and 15 of Moon Breathing for Michikatsu, if not I can do it myself.