I couldn't think of the names of the breathing forms LMAOOO.
MANGA SPOILERS!!

Also i'm adding the song "Another love by Tom Odell. It starts in the middle of the story!.

UNEDITED ITS LIKE 6AM RN
—

Y/n...Y/n knew she loved Iguro Obanai. It hurt her a lot to watch Iguro follow Mitsuri like a lost puppy most of the time.

Of course, she wouldn't stop it, she wouldn't try to attempt to break the "friends with benefit" relationship going on.

Mitsuri was oblivious to the whole situation not knowing Iguro was deeply in love with her even though she was the Love Pillar. Her love for everyone made her bubbly personality not notice "True Love".

Her personality truly did catch everyone's eye, I mean who wouldn't like a girl who is beautiful, kind, and caring? Her smile could brighten anyone's day, and her voice could make almost everyone blush.

Who wouldn't choose her? Who wouldn't love her? Who wouldn't want to be in her shoes? Who wouldn't want to brighten people's day? Who wouldn't want to save anyone in an instant? Who wouldn't want to be as strong as her? Who wouldn't fall in love with her?!

But of course...Y/n wasn't enough in her own eyes. She was the Rain pillar, her breathing brings wind, harsh damage, not a pleasing aftermath, and not a very graceful breathing for a "female" in others eyes. The breathing was made for destruction and was not "appropriate" for women.

Insect breathing and Love breathing were a very graceful and beautiful breathing for a female. Many wondered why Y/n's wasn't?

Y/n sighed leaning her back against the tree slouched on the ground picking a flower. The flower being slowly torn piece by piece by Y/n's hands, "Maybe...I'm not made to be loved..?" Y/n mumbled to herself.

She was picking more flowers on the ground until she saw a white snake slithering towards her. The white snake, Kabarumaru, belonging to the one and only Serpent Pillar, Iguro Obanai.

Y/n reached her hand out extending her index finger and gently rubbing the top of the snakes head. Kabarumaru leaned into her touch and hissed happily. Y/n smiled and extended her arm out signaling the snake to wrap around her arm which the snake happily did.

Kabarumaru slithered on her arm to her neck nuzzling his head to her cheek. Y/n lightly giggled and pet the snake once again. "Let's go give you back to Iguro-san," Y/n said smiling.

I wanna take you somewhere so you know I care. But it's so cold and I don't know where

Y/n searched around the Demon Slayer Corps only to find Iguro madly blushing under his mask talking to a smiling Mitsuri. Y/n waited till they were done talking she did not interrupt them, and once they were done she went to him and she saw Iguro's soft eyes turned to cold ones.

I brought you daffodils in a pretty string
But they won't flower like they did last spring

Her heart felt like it was being squeezed, her chest felt tightened but she still held her smile. "Iguro-san, Kambarumaru was by me and I just wanted to return him," Y/n said. The serpent pillar nodded and extended his arm out making his snake slither towards him in an instant. Iguro didn't even bother to look back he just walked away in the opposite direction Mitsuri left to.
Y/n sighed and walked away as well.

And I wanna kiss you, make you feel alright
I'm just so tired to share my nights

Those memories playing in her head all those times she helped Iguro. The reason why Mitsuri has those green socks was because of Y/n, she chose them out for him to give to Mitsuri. The reason why his haori is always together was because of Y/n was there to stitch it up.

I wanna cry and I wanna love
But all my tears have been used up

All those times she was there for him yet it was never in return. It was a one-sided love, and god did she hate it but it was reality. Reality hurts but it helps you face the future with a braver and stronger heart.

But what Y/n didn't know was Iguro was feeling the exact same way. Mitsuri's loving personality caused everyone to love her back, and her oblivious state made him slightly impatient.

On another love, another love

But when he found out Mitsuri had gotten a lover his heart ached. All those times he spent with her, the things he got her were all a waste... she was never going to be his.

All my tears have been used up

After Mitsuri had gotten a lover he didn't want to give anyone the same affection he showed Mitsuri again. He didn't even go out to eat with her anymore, but he also never disrespected her at all. He still showed his respect and always had small talk, but he never gave her gifts or took her out to eat anymore.

On another love, another love
All my tears have been used up

He doubted himself, was he too weak for her? Is that why she didn't notice his feelings?

-

On another love, another love
All my tears have been used up

When Y/n finds out about the relationship between Mitsuri and her new lover the first thing that went to her mind was; 'Is Iguro okay?'

Every Hashira knew about his little crush on Mitsuri.

She went by the Serpent Estate to see him training, well overworking himself. Y/n knocked lightly on the side of the wall for him to know she was here.

Her heart raced at the thick aura, he was taking his anger out on his training.

His hands were all blistered and bleeding and his bandages weren't changed. He looked a mess.

She waited for him patiently slightly panicking at the angry aura.

And if somebody hurts you, I wanna fight

And when she did, all he did was glare at her and walk closer to the entrance "What are you doing here?" He said. Y/n sighed and said "I just came to check on you. You haven't been going on your missions lately."

But my hand's been broken, one too many times

Iguro rolled his eyes "That's my business and it's none of your concern." He spat. "It is my concern because you're my comrade. We are all a team and we should all be there for each other." Y/n said back attempting to reason with him.

So I'll use my voice, I'll be so fucking rude
Words they always win, but I know I'll lose

Iguro just wanted to be alone, he harshly glared at her once again "We are not comrades, we are not friends, we are not anything. Do not come to check on me when you don't even check up on yourself. Go back to training you are still weak even with that destructive breathing of yours. Pathetic." He spat. He could have sworn he saw Y/n's eyes lose the sparkle when he said that to her.

He slammed the wooden sliding door shut.

And I'd sing a song, that'd be just ours

Y/n's heart just ached, even more, all those times she treated him, and that all meant nothing.

But I sang 'em all to another heart

Iguro on the other hand clenched his fist in anger and threw his sword at the training dummy making it crash to the ground.

'What did I do wrong Kanroji?..' Iguro thought.

And I wanna cry, I wanna learn to love
But all my tears have been used up

after that day Y/n no longer smiled as wide as she did before. An only a small smile would appear here and there, she greeted everyone but Iguro.

On another love, another love
All my tears have been used up

She was following his words "We are not comrades, we are not friends, we are not anything.".
-
Hashira Training:

Ever since some of the Upper Moons have been eliminated and Nezuko has been allowed to walk in the sunlight fewer demons have been appearing.

On another love, another love
All my tears have been used up

This gave some time for slayers to be trained by the highest and strongest-rank demon slayers. The stations were first

Uzui Tengen: Physical Fitness

Tokito Muichiro: High-speed movements

Kanroji Mitsuri: Flexibility

L/n Y/n: Combat Training

Iguro Obanai: Swordsmanship

Shinazugawa Sanemi: Strike training

Himajima Gyomei: Strength Training

On another love, another love
All my tears have been used up

When Tanjiro went to Y/n's training ground his positive energy and motivation to turn his sister back into a human always brightened Y/n's day.

Her smile would widen and she thought of him as her little brother who she lost for a Demon.

I wanna sing a song, that'd be just ours

One day when Iguro was walking around the corps taking a break from training those pathetic slayers he saw Y/n and the person he hated most Kamado Tanjiro.

But I sang 'em all to another heart

He saw Y/n and Tanjiro practicing combat moves, Y/n was striking at him with kicks and punches which he dodged all at the last second. Y/n struck one last kick at Tanjiro which hit his stomach making him fly across the training field.

Y/n ran to him and said "Ah I'm so sorry! I must have hit you too hard!" She apologized multiple times. Tanjiro just looked up at her with a wide smile "That was amazing! Can you teach me how to do that! I want to be as strong as you!" He yelled.

Y/n froze and looked at the boy who was begging.
Y/n lightly laughed and patted his head, her true smile, the big smile she used to show to all was now showing to Tanjiro. Tanjiro turned red and laughed as well holding onto his stomach still feeling the stinging pain. The smile Y/n was showing made Iguro's heart flutter but again that smile wasn't to him it was to Tanjiro.

And I wanna cry, I wanna fall in love
But all my tears have been used up

And Iguro did not like that one bit. His heart filled with more hatred towards the boy and jealousy consumed his whole body.

On another love, another love
All my tears have been used up

He glared at the two one last time and walked back to his Estate. His snake was still glaring at the boy while his owner walked away.

-
Tanjiro passed Y/n's training and he was truly happy with what he learned over the few days that helped him with the amount of force he put into his swords.

That was it, swordsmanship...which was Iguro Obanai's training next.

Y/n waved goodbye to Tanjiro smiling and walked back to her estate. Tanjiro yelled "Bye L/n!! Thank you so much!!" he turned around to see an angry serpent pillar

On another love, another love
All my tears have been used up

"Tanjiro Kamado, I've been waiting for you!" Iguro said glaring at Tanjiro. "I'm looking forward to-" Tanjiro tried saying but Iguro interrupted him "Shut up or I'll kill you."

"Huh?!" Tanjiro was beyond shocked.

On another love, another love
All my tears have been used up oh oh, oh

"I saw you with L/n! It seems you both have gotten quite close! I won't go easy or be as sorry as L/n was!" Obanai said glaring harshly at Tanjiro.

'From the very start...he totally hates me.' Tanjiro thought.
-

Over time everyone has been doing training and Hashira vs Hashira. Right now it was against Shinazugawa and L/n. Y/n still showed her small smile not showing any fear while Shinazugawa showing a menacing smile.

Iguro was on the branch gripping it tightly, he was worried for Y/n's state. Shinazugawa was a merciless man who wanted to prove he was strong and could win. While Y/n was a person with patience and wanted to help others, yet her breathing said something different.

"Go!" Shinazugawa yelled, Y/n leaped in the air "Rain breathing second form: Storm of the sea" Y/n mumbled. Harsh wind blew around them and her sword grew around Shinazugawa. Sanemi jumped through her swords "Wind breathing Eighth Form: Primary Gale!" Sanemi now leaped into the air swinging his sword making a bunch of slice attacks going towards Y/n.

Y/n dodged all of them, forcing her body to turn and to bend, Y/n forced her body forward making her flip and go right at Sanemi "Rain Breathing Fifth Form: Rain of destruction!" Y/n slammed her sword down making all of Sanemi's attacks disappear and the ground shake.

Y/n aimed her sword at Sanemi and Sanemi blocked her attack quickly. Y/n kicked him in the leg making his stance have a weaker stance. "Rain breathing Thir-" "Wind Breathing Sixth Form: Black Wind Mountain Mist!" Sanemi was quicker than Y/n. It was like tornado slashes were coming towards Y/n, Y/n leaped back "Rain Breathing Eleventh Form: Droplets of the Yinglong!" A huge dragon appeared behind Y/n going through Sanemi's attack and striking Sanemi.

The gush of wind made dirt fly everywhere, Mitsuri's face was covered from the fear of the outcome, Giyuu, Shinobu, and Muichiro were closely looking to see who officially won. Obanai grip on the tree tightened even more. Gyomei had his hands together worried from the quietness that was heard.

The fog was now going away only to show Y/n on top of Shinazugawa with her sword over his throat. Obanai sighed in relief as Y/n had minor injuries and won the battle.

Y/n got up and let her out for Shinazugawa to get up, he rolled his eyes and took it. "I'll get you next time L/n," Sanemi mumbled into Y/n's ear then walked away. Y/n'a face heated and she looked away from the scarred man. Obanai glared at Sanemi's back and motioned Kaburamaru to go to Y/n. The snake slithered off of Obanai and went towards Y/n crawling up her leg, Y/n looked down to see a white snake and smiled.

"Hello, there~," Y/n said putting her sword back and picked up the snake. Y/n walked towards Obanai and said "Iguro, Kaburamaru wandered off again.". Obanai looked down and jumped off the tree, "I apologize, he tends to wander off lately." he let his arm out and Kaburamaru hissed at his arm and glared at his owner.

Y/n silently laughed and said, "He seems to be angry at you for something." Obanai sweatdropped and looked at the snake putting his arm closer the snake looked away and nudged his head towards Y/n's cheek.

Y/n lightly laughed again and rubbed the snake lightly with her index finger. Y/n extended her arm out near Obanai's and the snake slithered to his owner's arm.

"We are not comrades, we are not friends. We are not anything." Iguro'a words repeated in her head again.

Her small smile faded into a neutral face "Goodbye Iguro, I have to go train more." Y/n said going towards the second person Obanai hates the most. Tomioka Giyuu.

Obanai saw her facial expression change like she remembered something. He followed her and grabbed her arm making her get pulled harshly towards him.

She snapped her neck towards him confused and Obanai quickly let go of her arm. "...I apologize I don't know what came over me.". Y/n still held the expression of confusion but nodded either way. She continued to walk towards The Water Pillar.

-

Final Battle:

Y/n was fighting against Upper Moon 1, alongside Muichiro, Genya, Sanemi, and Gyomei. The Upper-Rank demons attack were powerful, his breathing forms and his ability to heal was a disadvantage to Y/n. Y/n had cuts all over her body, she stood up still glaring at the Upper-Rank demon.

Kokushibo felt a cold glare and a heavier aura in the area, he turned to face it to see the woman he threw across the fortress. 'She's still alive even after my attack...truly good swordsmanship.' he thought. Y/n leaped towards him, swinging her sword aiming for his neck, Kokushibo blocked the attack quickly and swung his sword at her arm.

Y/n ducked dodging his attack, she was swinging her sword at him in many directions, her main goal was to weaken him or tire him down. Kokushibo jumped back "Moon Breathing Seventh Form: Mirror of Misfortune - Moonlit!" He swung his sword making multiple powerful slashes go towards Y/n, instead of running Y/n ran towards them making Sanemi yell "Are you crazy!!". Y/n ignored him and leaped towards the demon's attack "Rain Breathing Fifth Form: Rain Of Destruction!" the same attack she practiced on Sanemi she used on Kokushibo.

Y/n slammed her sword to the ground making all of his attacks disappeared and the only different thing was when she slammed her sword down slashes started to circle Kokushibo. Y/n's hands were shaking, now from fear, but from anger. She knows she might not win this battle, half her comrades are either dead or are down.

Y/n looked to see Muichiro wounds being treated by Genya as his hand was sliced off at the beginning of the fight with the Upper Moon. 'Genya...GENYA! If I get at least a chip of the upper moon's sword or anything that's a part of him and let him eat it won't he turn into a demon?' A loud crash from the ground was made.

The upper moon had broken out from the cage circle. Y/n, Gyomei, and Sanemi attack the demon all at once.

*Skip to fighting Muzan cause I got to school and I'm currently crying over Itachi's and Sasuke's scenes*

Muzan was coming for Y/n, she was the one who succeeded in slicing off his head but it grew back in an instant. He saw her as the biggest threat out of all of them once she did that, the attacks he was sending her were overwhelming.

She was already tired from her last battle between Kokushibo and her comrades. She lost two of them, Muichiro and Genya. The death of Muichiro made
Y/n, even more, angrier and the death of Genya made Sanemi feel the exact same way.

They were both too young to die, especially at the hands of a demon in the most painful way. Y/n dashed towards Muzan "Rain Breathing Ninth Form: Harsh rain of the sea!" Her attack slashed Muzan's body in an instant and as her sword began to glow red Muzan used his sharp tentacles to slash her. His tentacles all at once attack Y/n, Y/n attempted to block all of them but it was to fast. Her eyes widened as a tentacle came from behind stabbing her through her chest and one slicing her body.

Y/n lost her balance and fell to the ground dropping her sword. Muzan began to attack the others thinking Y/n was already down.

'She's down, i don't need to kill her my poison will. Now i can focus on destroying the rest.' Muzan thought sending his tentacles towards the other Hashira's. Obanai, Sanemi, and Giyuu were all fidgeting Muzan's attack. Obanai got sliced in the process trying to get close to Y/n.

Giyuu spaced out once he tried to cut through Muzan's attack but his sword lost his grip. Y/n got up and dashed towards Giyuu blocking the attack Muzan but getting sliced in her arm.

Blood was coming out her mouth and her hands were shaking from the poison. "Stop spacing out! Fight to the end! Your the Water Hashira! Tomioka Giyuu! " Y/n yelled. Y/n ran towards Giyuu clashing her sword with his making it turn glowing red.

Y/n smiled before rushing off towards Muzan, Obanai saw Y/n her body was in no condition to fight yet the determination in her eyes said other wise.

Muzan turned to see Y/n running towards him once again "Why can't you just stay dead!!" Muzan yelled sending multiple attacks. Y/n was quick to leap through them all, "Rain Breathing; Ninth form! Harsh Rain of the Sea!" his attacks were destroyed and Y/n's bright red blade cut through his attacks easily.
.

"Die!!" Muzan yelled. Muzan grabbed Y/n by her throat and squeezed it. She grabbed her sword and stabbed his face which had no effect on him. "L/n!!" Iguro yelled. Y/n was not gonna die like this. She was the one to cut off Muzan's head not once but twice. And this is how she dies? Being chocked by him?! No!

Y/n shakily lifted her sword up and as she was about to strike a huge attack hit Muzan making him drop Y/n and fly back. Y/n dropped to the floor and began to cough.

She looked who had saved her and it was Tanjiro. Tanjiro stood in front of Y/n gripping on his sword tightly "Can you still fight Y/n-san?" Tanjiro asked. Y/n stood up slowly still coughing "Y..Yes I can.".

Iguro went right beside her and said "You've done enough. Let me and the others handle the rest L/n.". Y/n shook her head trying to catch her breath. "I'm going to continue to fight until I see him disintegrate." Y/n said looking at him straight in the eye. Iguro looked at her and hesitantly nodded "Once I see you down that's enough. I'm taking you away from battle." he said seriously.

Y/n looked at him and nodded, they both dashed towards Muzan "Rain Breathing Second Form: "Storm of the Sea!" "Serpent Breathing Fifth Form: Slithering Serpent!"

Iguro's sword curved around Muzan slicing his body in different places while Y/n's sword started to grow around Muzan's body trapping him while spinning.

"What a perfect duo." Muzan flatly said glaring at both of them, Tanjiro soon stepped in and started doing powerful attack at Muzan.

Y/n jumped back and Iguro did the same. "Tomioka, since both of your breathing forms connect with water is it possible for you both to put one together?" Iguro asked.

Giyuu nodded and looked at Y/n whos arm was still bleeding out from taking his hit. Himejima, Shinazugawa, and Kanroji were all helping out Tanjiro with his attacks.

"I can do my strongest breathing along with yours
L/n and Iguro can connect it by trapping Muzan and we all corner him." Giyuu said.

Y/n nodded while ripping a piece of her Haori to stop the bleeding and Iguro nodded as well. "Ready?" Y/n asked as she picked up her sword and looked at the other Hashira(s), trio, and Kanao struggling a bit.

They both hum in response, Y/n, Iguro, and Tomioka all dash towards Muzan prepared to end his life right then and there. "Serpent Breathing First Form: Winding Serpent Splash!" "Water Breathing Tenth Form: Constant Flux!" "Rain Breathing Eleventh Form: Droplets of the Yinglong!"

All those attacks together made a huge impact and force. Iguro's attack trapped Muzan but also slashed him all at once while Tomioka's slashed him in multiple directions. Y/n's attack made a dragon slice through all the recent attacks Muzan made and go after him. The dragon roared loudly and charged at Muzan slicing his head off once again.

The others were on the ground injured or dead. Y/n looked around and Tanjiro began to attack again nonstop. But out of where Muzan went close to Tanjiro and his face was splitting in half.

Muzan's face split in half showing a bunch of sharp teeth and he aimed for Tanjiro's face. Y/n ran towards Tanjiro getting in front of him making her face get bit instead.

Iguro's and Tomioka's eyes widened in horror. Iguro ran towards them as quickly as possible with Tomioka following along.

Tanjiro's eyes widened as well at her sudden move, Y/n let out a scream but quickly punched Muzan under his chin and kicked him making him fly back.

Y/n grabbed her sword once again and ran towards him. Tanjiro got up to follow her and grabbed his sword. The sun was rising and Muzan began to turn himself into a big baby like form.

He attempted to grab Tanjiro but Y/n shoved Tanjiro out the way "Rain Breathing Twelfth Form: Tears of the Death!". The ground shook and Y/n stabbed through Muzan's new form making him fall back. Muzan attempted to crawl away but the Kakushi's tried to stop them by using cars to get in his way including a bus.

Muzan swapped Y/n away making her fly towards one of the buildings. The Kakushi's pushed a train trying to stop him from running away and thinking they were all gonna die Shinazugawa and Himajima stepped in.

Iguro tried to find Y/n through the building she went through but found nothing. He began to panic,
"L/N!!" L/N!! WHERE ARE YOU!!" He yelled.

He heard more commotion going on and closed his eyes. 'I'm sorry Y/n..' he thought tears streamed down his face and he gripped his sword tightly. He ran towards the noise only to see Y/n on top of Muzan's form stabbing him with the rest of the strength she had. Her sword went through him to the ground along with Himajima chains holding him back.

Muzan stabbed Y/n through her chest with the rest of power he had still having hope he could escape. Was he wrong? Yes...very wrong, she still continued to hold her strength through her sword with blood coming out her mouth. Muzan let out a scream as the sun began to disintegrate him.

Y/n fell back expecting to hit the ground but Iguro caught her before she could. He gently put her down and yelled for Kakushi's to treat her. "She's bleeding out!! Hurry up!!" he would yell, Y/n was on the floor breathing slowly.

Iguro was hurt bleeding out as well but he didn't care. All he wanted was for Y/n to be safe and alive. He held her hand putting pressure onto it "Squeeze my hand L/n. Please...please just stay alive." He said with tears falling down his cheek.

Y/n squeezed his hand but it was a light squeeze, her face was half bloody from Muzan biting her, her arm had a deep slash that wasn't treated properly, and her new wound Muzan made before dying was bleeding out fast.

He took off the last piece of his haori and put pressure on her wound. "...r-remember when I would always come back from my mission with my haori ripped. I...I never got to thank you for always fixing it for me." He said trying to keep her awake.

"It's...okay." Y/n said lowly, her voice sounded weak and her heart rate was getting slower and slower.

"Nee-san!! Nee-san!! You did it!! You finally did it!!" Y/n's little brothers voice was heard. "I've been waiting for you!!"

Y/n eyes teared up and she looked at Iguro. "...I-I won't have much time Iguro...I have been wanting to t-tell you this." Y/n tried saying before interrupted by a blood cough. "I have always loved you...even though you loved someone else. I never stopped loving you.".

Iguro's eyes widened at her sentence, all those things hes done to her, ignoring her, not giving the same attention back, and simply falling for a person who wasn't in love with him. The real person he loved was right in front of him.

Iguro gently pulled her onto his lap and held her close. "...I hope to see you again L/n. M...Maybe in another life time we can be together and be happy." He said smiling weakly. Y/n hummed in response before closing her eyes. "No...no no no no. Wake up Y/n." Iguro tried shaking her but it was no use she wouldn't wake up. He too began violently coughing and still had tears stream down his face.

"I wish I told you I loved you sooner rather than now..." Iguro said before slowly collapsing down next to Y/n hugging her cold body.

"...I will meet you again and we will be happy...it's a promise." he said weakly before closing his eyes.

-

"WOAH!! That's so romantic but so sad!!" Makamo said as Sabito and Giichi closed the book they all three were reading.

"Are you crying Giichi?" Sabito asked. "N-no my eyes are just sweating!" he said making Sabito chuckle. Makamo smiled at Giichi, "I believe they did reunite together. Love is the strongest thing that can keep two together! The love can be bad or can be good...but love is unstoppable. We cannot control who we love." Makamo said.

Sabito clapped his hands as he was playfully applauding her. "Good job for the speech Makamo." They all laughed together.
-

Y/n walked around into the school, she was back from her lunch break and she needed to come back to class early to prepare her lesson.

She was a new reading teacher in school, and so far the nicest one yet. Many students always loved going to her class since she would always have fun activities planned out.

Y/n was looking at her printed paper she just made while walking down the hall way until she bumped into someone causing her to drop all her papers.

"I'm so sorry! I wasn't looking where I was going" she apologized as she bent down to recollect her papers. The person in-front of her also bent down to help and once they were finished collect the scattered papers they both looked at each other.

"I'm L/n Y/n...the new teacher. Again Im sorry for bumping into you.." Y/n said as the person handed her paper to her.

"...It's alright. I'm Iguro Obanai, I am one of the Chemistry teachers." He said as he can feel his face heat up from her beauty.

(fuck chemistry.)

Y/n smiled "It's nice meeting you. I hope I see you around and we can talk more." she squeezed his hand and walked away.

Iguro felt like he has seen her somewhere and the way she squeezed his hand felt so familiar made his head thump.