Four months ago, Y/N is outside of Mitsuri's house training. He's on his knees while drenched in sweat. He's breathing heavily while she looks down at him with one hand on her mouth. "Uh, Y/N, I think we shoulder stop," she said.
"Come on," he said while wiping off the sweat from his forehead. "One more time!"
He got into a sword stance.
His body was visually shaking and it appeared that his legs were going to give out at any second. His arms seem like they were using every bit of strength they had in them just to hold the sword and didn't like that they are able to swing the weapon.
"Y/N," Mitsuri said while putting her sword away. "No."
His ankles buckle and he falls to his knees. "Y/N!" she said while rushing over to him. It had seemed that he was done and wasn't going to do anything. "Y/N," she said once again while cupping his face in her hands. "I think we should stop."
"Alright," he replied. "But we'll continue later on."
"Can it be just normal training?" she inquired.
He slowly gets up and turns his back to her. "You know I have to learn Flame Breathing," he retorted.
"Well, you don't have to," she told him.
"You know what I mean."
"Can I ask you a question?"
"What is it?"
"You developed Rage Breathing because you couldn't get the hang of Flame Breathing, right?"
"Yeah."
"Then why are you learning Flame Breathing now when you already got Rage Breathing and you know that Flame Breathing is hard for you to learn?" she asked him. He turned back to glance for a second before turning his back to her again. He didn't say anything and she looks at him with worry. "Is it because of Rengoku?"
"Yes," he answered with a sigh.
"Y/N," she said while standing up and walking over to him. She grabbed the wrist of his right arm and turned him around to face her. "I understand that you admired him but you don't have to learn the Breathing Style that he used. You created Rage Breathing for a reason."
"It's not that simple," he replied.
"What do you mean?"
"It's about when I mean Akaza again," Y/N answered. "When I meet that bastard again, I will kill him. And it will be with the Breath of the person that he killed."
"Y/N, I understand that you're filled with rage, but you shouldn't let that blind you. I don't want to sound rude, but I think you should give up on learning Flame Breathing," she suggested.
"YOU DON'T UNDERSTAND!" Y/N snapped.
He proceeds to walk away while Mitsuri runs over to him. "Y/N!" she said while jumping for him.
"What is going on here?" asked Obanai.
They both look and see him standing in front of them. "Nothing. This doesn't involve you," Y/N answered before walking away.
He walked past the Serpent Pillar and went on his own to train. He enters the middle of a forest in a nice open and grassy area. "Perfect," he thought before readying his sword. "Flame Breathing, Second Form: Rising Scorching Sun!!"
He performed the move but failed in getting any results out of it. "Damn it!" he said before pulling out a book about Flame Breathing. "What did I get wrong?"
"Everything," a male voice answered.
"Huh?" he said before turning around to see Obanai. "What are you doing here?"
"I don't want to be here either. I'm only here at Mitsuri's request," he informed him.
"Well, leave me alone. I don't need help from someone like you," Y/N replied. "Flame Breathing, Second Forming, Rising Scorching Sun!"
He tries to perform the action but Obanai grabs his left wrist. "I understand that you want to kill Akaza with the same Breath as Rengoku's, right?" the Snake Hashira asked him.
"I do," he answered while struggling to get out of his grasp.
Obanai kicks Y/N several feet away. Y/N skips across the ground as if he was a peddle being skipped around a pond. He eventually gets on his knees and looks at the Serpent Pillar while breathing heavily.
"That'll never happen," Obanai told him. "Because you are not Rengoku."
"What are you talking about?" Y/N asked.
"You are not Rengoku. He was better than you in every single way. You are not the warrior that he was. You are simply a boy with too much anger," Obanai bluntly told him.
"I don't care what you think!!!" Y/N screamed before running at him. "Flame Breathing, First Form: Unknowing Fire!!"
He charges at Obanai at great speed but doesn't no flames are generated. Obanai dodges it effortlessly and smacks him away. "This is a perfect example. If that was Rengoku, I would have had to try to dodge the attack," Obanai told him.
"Just shut up!!" Y/N screamed before going back in. "Third Formn: Blazing Universe!!" He performs the action but no flames appear. "Damn it!!!"
Obanai slaps him and causes blood to drip out of his nose. Y/N falls to his knees while holding his hand under his nose to catch the blood. "This is your problem," Obanai said while looking down at him. Y/N looks up to hear "you're trying to be Rengoku. You'll never be like him. There is only one Rengoku and you can't be like him."
"I get it. I understand that I'm not him and I should give up on trying to learn Flame Breathing," Y/N replied.
Obanai kneels. "I'm not saying that," Obanai told him.
"Huh?!" responded Y/N. "You just said that I'm not like him!"
"I did but I didn't say that you couldn't learn Flame Breathing. While I do think that you're stupid for learning it but you can learn it," Obanai explained.
"Thanks?" Y/N said very confusedly.
"What I believe is stopping you from learning it is because of your rage," Obanai said. "Your rage is unrefined. It's wild and blinding. You're learning Flame Breathing just so you can use it to get revenge. You're not taking your time to learn it. You just expect it come naturally because of your rage. Instead, use your rage to guide you instead of blinding you."
"I think I get what you're saying," Y/N retorted while standing up.
"Good. Now use that rage and actually do something correctly," Obanai told him.
Y/N breathes in and out. He controlled his breathing and was going to use it correctly this time. He opens up his eyes and lets the air enters his body. He charges forward and shouts "Flame Breathing, First Form: Unknowing Fire!!!"
Flames begin to form around his sword and he swung it. Both Y/N and Obanai looked on in amazement. He did it. He actually used Flame Breathing truly. "Good job," Obanai told him.
"Thanks," Y/N replied before putting his sword away.
"What are you doing?"
"I need to do something before I continue to train," Y/N told him before running away.
"Figured."
Y/N ran back to Mitsuri's house and sees her house while looking at some flowers. "Mitsuri!!" he shouted.
"Huh?" she said before turning to him. "Oh..."
"Hey."
"Yeah, hey..." she responded.
"Mitsuri," he said while placing his left hand on her shoulder. "I'm so sorry. I know you were just worried. I shouldn't have snapped. Please, is there any chance you could forgive me?"
"Of course. I'm not one to hate," she told him.
"Thank you!" he told her before wrapping his arms around the woman.
She hugs him back as Obanai comes in to say "he learned how to use Flame Breathing."
Mitsuri lets go and asks "really?!"
"Yeah," Y/N answered.
"That's great!" she replied. "Thank you so much, Obanai!"
"It's no problem," he retorted.
Mitsuri's stomach suddenly growls. "Time to eat," she said with a chuckle before walking away.
"Hey, Y/N," Obanai said.
"Yeah?"
"I see that you and Mitsuri like each other."
He slightly blushes. "Yeah... we do."
"Take good care of her," Obanai told him. "Or I swear, I will kill you."
"Got it..."
"Now, let's continue."
"Let's."
Both Demon Slayers got ready to continue the training. Over those four months, Y/N would gain a much better understanding of Flame Breathing and how to understand it. He wasn't going to stop until he had fully mastered it and wouldn't use it until he had it under control.
Present Day, Y/N wakes up from his short sleep. He looks around and hears the sound of people fighting a fair distance away. He grabs his sword and makes his way over there as quickly as he could. He gets to the scene of everything and sees Tanjiro holding Nezuko back with his sword in her mouth.
"Go to sleep," he told her.
She only responds in incoherent sounds. Meanwhile, Daki walks over to them with half of her face burning. "This is extremely pissing me off right now. First I get stabbed, the second I get my neck nearly cut off, and third, I'm burning!!" she screamed. "I swear, I'm going to kill you!!"
This was his chance to finally kill her. He steadied himself and got ready to end this all. He controlled his breathing and remembered the phrase "Kar Ren Tuk."
"Flame Breathing, First Forming: Unknowing Fire!!" he said before charging in after her. She turns around and uses her sash to smack him away. But the sash was burned and he continued. "What the-"
Y/N slices it clear right off. He clams himself and looks back at Daki's body as it held onto the head. "Finally..." he said while falling to his knees.
Clapping could be heard. Both Tanjiro and Y/N looked and see Tengen was the one doing it. "Man, I never thought I would say this to you, but that was a surely flamboyant way to kill that demon!" Tengen told him.
"I... am not going to argue," he said before laying down on the floor.
"This fight isn't over yet. Boy, get control over your sister," Tengen told Tanjiro. "Sing her a lullaby or something."
Tanjiro and Nezuko go out the window and the red haired boy does his best at trying to calm down his sister. He manages to do so while Tengen looks over and says "good job."
"Thank... you..." Y/N responded. "And it was an Upper Moon too."
"You think that was an Upper Moon?" Tengen asked him. "She ain't no Upper Moon. Still, good job though."
"WHAT?!" Daki shouted.
"You still alive?" Tengen asked while standing up.
"What do you mean I'm not an Upper Moon?!" she asked him.
Tengen keeps on explaining how she can't be an Upper Moon and Daki proceeds to throw a tantrum. Through all of this, something begins to grow out of her body. Both Tengen and Y/N were extremely confused. Not wasting any time, Tengen goes in to kill whatever was coming out of her.
The being dodges his attack and comforts Daki. Y/N looks at the monster and thinks "what the hell is that thing? It's so fast and is not something to underestimate."
Once Tengen sees him comforting her, he goes in for another attack. The demon dodges and tries to attack Tengen but he manages to stop the attack. "Nice... real niiiiiiiiiiiiiiiiiiice," the demon said impressed by him stopping the attack.
Gyutaro goes on to compliment Tengen and talk about how much he envies him and how he wants to kill him. "My cute little dumb sister worked so hard and she shouldn't be dealing with this. It's time to collect the debt," Gyutaro said before unleashing an attack aimed towards Tengen.
Y/N saw the attack coming and didn't know what to do. His body could barely move. But he knew this wasn't the end. Tengen had grabbed him along with the other humans in the area that would be affected by the attack and protected them.
"The envy, maaaaaaan. You really are a niiiiiice guy," Gyutaro told Tengen. "Protecting humans while looking so cool. Niiiiiice."
"I'm a flamboyant ladies' man. So, course of. I even got three wives," Tengen retorted.
"Three wives?! You're kidding me, right? RIGHT?!" Gyutaro asked him.
Seeing this, Y/N took this chance to stand on his own two feet and grab the two other humans. He turns to Tengen and tells him "kill that bastard. Flamboyantly."
Tengen smirks. "I already planned on it."
"Good," Y/N said before leaving with the two humans. He gets a fair distance away as the sounds of fighting roars behind him. Once he feels that they have gotten somewhere safe, he drops them off and says "stay safe."
"We will," they said before running as fast as they can.
Y/N body was still hurting badly but he knew that he had to help and keep fighting until his body stopped working altogether. He ran back in and jumped into the action along with Inosuke, Tanjiro, and Zentisu.
"Some of your underlings just came, but there won't be a happy future waiting for you, man," Gyutaro told Tengen. "You're all gonna die."
Y/N scanned Gyutaro and thought "this guy is the real body. Cutting off the girl's head will do nothing. This guy is the one that needs its head cut off."
"We will win!!!" Tanjiro announced.
"You all will die!! There is poison running through the Pillar's body!!" Daki shouted.
"We'll win easily!!" Tengen shouted back. "There may be poison running through my body, but I'm still running high!! Don't look down on humans!! These guys are my prize successors!! They won't run away!! They got guts!! I already know how we'll win!! Just cut both of your heads off at the same time!!"
"HAHAHAHAHAHAHAHAHAHAHAH!!!!" Inosuke laughed. "I see, it's so simple!! Of course, we'll win!!"
"It may be simple but not gonna be easy. Me and my sis have eaten Pillars many times. Fifteen for me and seven for my sis over there," Gyutaro retorted.
"That's right!! You all are gonna die!!!" Daki shouted.
Zentisu bounces around the room and takes Daki to the roof. "You guys leave Maggot girl to me and sleepy head and take care of mantis boy!" Inosuke told them before leaving.
Tanjiro and Y/N stand in front of Tengen and get ready for whatever will happen. They sense the bloodlust that was coming off Gyutaro and knew that the moment he moves, they needed to swing their sword to stop him.
He moves extremely fast with Y/N being the only one to see his movement. "Flame Breathing, Second Form: Rising Scorching Sun!!"
"Nice eyes, kid," Gyutaro said while he backed up.
Tengen passes through the two teenagers and begins to clash his blades with Gyutaro.
Both Tanjiro and Y/N watched and couldn't believe the countless amount of slashes. The roof above them was beginning to fall apart and was only adding to the difficulty of this fight. Eventually, at one point, Gyutaro found an opening and was going to stab Tengen in the back.
CLASH!!!
Y/N hand jumped in and stopped it from making contact with Tengen back by blocking it with his sword. Y/N felt the pure force of it and knew that he couldn't keep taking on the full force. Unless...
"Rage Breathing, Eighth Form: Feral Flash Dance!!"
Now with the added strength, he managed to deflect the attack. With that, Tengen uses the Fifth Form of Sound Breathing. Gyutaro smirks. "Overpowering me with a noisy Breathing Style. There's no point."
Tengen and Gyutaro keep clashing their blades as Daki kept sending her sash through the room they were in. Tanjiro and Y/N worked together to destroy the sashes and help the Sound Pillar in this situation. Y/N looked over at his friend and understood that he was pushing himself heavily. He was doing the same and it was a mystery how either one was still continuing to fight.
As the battle rages on, they end up outside and one of Tengen's wives unleashes a storm of kunai at the demon. One manages to land on his neck and numb him. Seeing their moment, Tanjiro and Y/N jump after him. All three go after the demon in hopes that this will be it and this battle will finally be over.
But his legs regenerate. "Damn it!!" They all thought.
"Man, that poison actually worked," Gyutaro told them. "Blood Demon Art: Round Slashes of Death Splatter Sickle!"
Tengen takes both Y/N and Tanjiro and tosses them aside. Quickly, Y/N got up and looked around and didn't see Gyutaro. "Where is he?!" Y/N inquired.
"Hina!!" Tengen shouted to his wife.
"Don't mind me, just look for the demon!" she told her husband.
Tengen is ready to attack but the sashes from Daki get in the way. "NOOOOOOOOOOOO!!!!!!!!!" he screamed.
Tanjiro uses both Water Breathing and Hinokami Kagura together and saves Tengen's wife. Gyutaro wasn't stopping and attacked Tanjiro. "First Form: Mad Judgement!!" Y/N screamed before his blade extended.
It blocked his attack and gave Tengen enough time to run in. "Y/N and Tanjiro, I am in your debt!!" Tengen told them.
Both of them take this chance and try to cut off his head. "COME ON!!!" Y/N screamed.
Gyutaro blocked their blades. "There's no way in hell I'm going to let you guys cut off my head," he told them while smirking.
"Flame Breathing, First Form: Unknowing Fire!!" Y/N screamed while lunging himself at the demon.
Gyutaro launches himself in the air with Tengen and Y/N ends up missing his target. "Damn it!" Y/N thought. "We have to win this!!"
Sashes surround them. "Inosuke!! Zentisu!!" Tanjiro shouted.
"We can't handle maggot girl," Inosuke told them. "Just give us a hand!"
Y/N looked at Daki and knew this wasn't going to be easy. "Just try to hold her off. Weh I shout 'now' get out of the way!"Y/N told his fellow Demon Slayers.
"Got it!" the sleeping Zentisu replied.
"Will do!" Tanjiro retorted.
"Don't tell me what to do!" Inosuke shouted.
"Alright then, I guess I'll take you out as well," Y/N retorted.
"I'll get out of way. Jeez," Inosuke responded.
Y/N readied his blade and held it over his shoulder. "Alright, I got this. After all of that training, I can't screw this up. I won't! Just breath! Breath! Breath! Breath! Let my rage fuel this attack! The most powerful attack that I have!!!!"
"Flame Breathing, Ninth Form: Rengoku!!!!!!!!!!!!!"
"NOW!!!!!!!!!!!" Y/N screamed at the top of his lungs.
He rushed at Daki just like how Rengoku did against Akaza during their battle. Daki uses her sashes but they were all burnt and she didn't have enough time to move out of the way due to him coming at her with such extreme speed. He reaches her and his sword cuts into her neck. It easily slices through thanks to the heat and speed of his attack.
Her head falls onto the floor and he kicks it away from the body. "Awesome!!" Tanjiro shouted. "You did it!!"
"Yeah..." Y/N responded. He was happy but his body was roughed up. His body has been pushed to its limit and he felt that his body was done for. That is when Gyutaro comes from behind and stabs Y/N in the back. "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH!!!!!!!!!!!!!!!!!!" Y/N screamed as blood spills out of his mouth.
He falls to his knees while covering his mouth. "Y/N!!!!!" Tanjiro shouted. "Shouldn't Tengen be..."
He looks over and sees Tengen lying on the ground not moving. The three other Demon Slayers look in horror at what was happening. The demon begins to wreak havoc on everyone until it was just Tanjiro and he left still awake.
Y/N lies on the roof of the house. As he lied there, he thought about why he is a Demon Slayer. He knows exactly why. It's because of the rage that fueled him when his family died. Now, it's the rage that fuels him with the trapped existence that demons have. But never seems to be enough. There are demons out that that simply excess his strength despite how much rage Y/N has.
All he knows is that he has to keep getting stronger and pushing forward. He hasn't forgotten his goal. Kill all demons and end it once and for all. He can't do it if he's dead. He has to stay up, grab his sword and end this battle.
Y/N slowly picks himself up and uses a breathing technique to seal up the wound that Gyutaro had created. Upon grabbing his sword, it glows a bright red. His rage was burning hot and was all he had left to use and finish this battle once and for all.
He stood on his two feet and saw Zentisu cut off Daki's head. She was something he didn't have to deal with now. Which was perfect. His feet began to move. It was simply walking. But walking began speed walking. Speed walking turning jogging. And jogging turned into running and soon enough, he was in a full on sprint.
"Rage Breathing... Eighth... Form: Feral Flash Dance!" he began to run even faster now. He jumped off the roof and sees Tanjiro and Tengen fighting Gyutaro. This was the perfect moment. He had to strike now. He lands on the ground and looks at them. He knew that Gyutaro's neck was tough and wasn't going to be so easily cut especially with what strength Y/N had in his now weak arms.
"Rage Breathing, Ninth Form: Total Vengence!!" Y/N said.
He rushed in on Gyutaro while he was dealing with the other two Slayers. He sees Y/N coming in and thought nothing more of him. The moment he got close, it would be over as he would simply smack him away and be done with it. "Rage Breathing, First Form: Mad Judgement!!"
The blade extends and causes Gyutaro's eyes to widen. He didn't expect the Slayer to combine his forms like that. Dealing with Tanjiro and Tengen was trouble enough but he couldn't get out of this one. Both the red haired boy and Pillar were on him and the range of Y/N's sword was massive.
Y/N swung and managed to hit the back of Gyutaro's neck. While the sword wouldn't naturally cut through, thanks to the Ninth Form, it forced its way through his neck and finally cut it off. A nice clean cut straight through and the demon was finally done with.
Or so it seemed. Y/N falls to the ground unable to move an inch. His mouth was done and couldn't be pushed any further. Gyutaro's body suddenly unleashes a wave of slashes everywhere. Y/N passes out.
It won't be a while until he wakes up again. It was a crazed battle and one that he'll always remember. One where he killed an Upper Moon demon. The boy who couldn't handle a demon that barely even comes close to the power of a Lower Moon demon now killed an Upper Moon. How far will he grow?
Word Count: 3903
Tengen: You were really flamboyant out there boy!
Y/N: If you say so.
Tengen: Come on, give yourself some credit!
Y/N: No.
Tengen: Really?
Y/N: Yes.
Tengen: Alright then, it's time for a Taisho-era secret! I hear that the Author's kitten slept next to them while they wrote this chapter!
Author: Cute little thing. He was kinda annoying though since he kept moving. But eh.
Anyway, I hoped that you enjoyed this chapter and I'll see all of ya in the next one. Peace!
By the way, I do plan on telling y'all about my weird dream about Demon Slayer. Just wanted to write this first.