Yandere! Haikyuu! x Reader

Kageyama Tobio

(A/N)~Thanks for reading everyone! May not be a lot, but it means a lot! :D
October 13 2014
A day you will never forget. Ever.
That day you made a terrible mistake. Something you can never take back.
You were watching the volleyball team practice. Observing each and every person in their skills and what they need to improve on.
~•~•~OOH A FLASHBACK~•~•~
Hinata needed to work on reviving ,as always, Yamaguchi was still getting his jump float serve, Daichi was practicing his serves, Sugawara was working on receiving, even though he's a setter, Tsukki was practicing his blocking skills, Asahi was practicing very powerful serves, Noya was practicing receiving, although you think he's already perfected his ways in receiving, Tanaka was practicing spiking while Kageyama was setting fast pasted sets to him.
Kageyama
He's never been too bright.
Never smiling. Almost always angry. Taking out his anger on either Hinata or himself. Not your type of guy though.
The only reason you became second manager of the team was because of all the hot guys in it. Most importantly, your best friend Asahi. You and Asahi talked very often about many different sports. The ones you understood and didn't. Then one day you both got into a heated conversation about volleyball. A sport you've always admired. One day he suggested you come and watch them practice. You gleefully accepted the offer, and now, three months later, you're here watching them practice.
You couldn't ask for anything better right now. You were happy in life. You had a best friend, something enjoyable to do, and a volleyball team that makes you feel like you're flying.
"Ok everyone practice is over! Tomorrow morning we have practice!" Daichi announced. That ended quickly. You looked over to the hard working boys again to see everyone cleaning up balls, taking down the net, and grabbing a quick drink of water before helping out some more.
"(Y/N)! Can you give me a quick hand?" You heard your friend, Asahi, call. Except you couldn't quite see Asahi. He was holding so many volleyballs his face was covered!
"Oh gosh Asahi! Give me some of those!" You scolded him as you took about half of his pile. "I know you like to help, but don't suffocate yourself!"
"Sorry! I just wanted to clean up quick so I could take you out for a quick bite. Im hungry and I know that you're always hungry." Asahi joked around as you and him dumped the balls into the bin.
"Oh you got me there. Maybe we can stop by Ukai's and grab some pork buns!" Your mouth watered at the thought of them.
"Sounds good! Just as long as I pay!" The ace smirked.
"Asahi Azumane if you pay a single cent you will not wake up tomorrow." You darkly said, but of course you were joking! Asahi was just too busy running away from you out of fear.
"Oi (Y/N)! What'd you do?" You turned around around to see Nishinoya with a smile on his face. Out of the corner of your eye you saw someone staring. Kageyama was staring. You thought nothing of it though.
"I didn't do anything!" You innocently put up your hands. "I just...uh...threatened to kill him if he payed for the pork buns that I AM BUYING!" You made sure to emphasize the final three words so Asahi could hear.
"You're not buying them (Y/N)!" You heard Asahi say from somewhere.
"Hah! You two are so cute." Nishinoya said as he started walking towards his duffel bag. "I can't wait until you guys become a couple."
"W-what?!" A blush immediately took over your cheeks. "W-we're just friends!"
"Yeah! 'Just friends.' " Noya had a playful smirk on his face now.
"Nishinoya...You've gotta stop shipping us together! I don't  want things to get awkward..." You said looking off to your smiling friend talking to his fellow third years. Before you turned your head you saw Kageyama again. Glaring a thousand daggers at Noya. Still, though, you thought Kageyama was being himself.
"(Y/N)! Lets get going?" Asahi yelled out to you.
"Yeah sure gimme a second!" You hollered back. "Cya Noya!" You waved at him before walking to Asahi.
"Oi Asahi! Make sure you kiss her!" Noya called out. Both you and Asahi were now madly blushing.
"NISHINOYA YUU I WILL MA-" You began yelling out until someone started to drag you away.
"Ok Noya I'll make sure we kiss!" Asahi called one last time before you and your friend stepped out into the cool night air.
"Sorry about that..." You mumbled as both of you made your way to your delicious destination of pork buns.
"Its not your fault. I know that Noya can be a bit....enthusiastic." Asahi sighed.
"I'd say crazy, but enthusiastic works too." The both of you chuckled and made some talk about volleyball until you reached the store. The second you entered you immediately ran up to Ukai.
"Make sure Asahi doesn't pay!" You said already taking out your money.
"Sorry (Y/N) but you're gonna have to be a bit quicker next time." Ukai replied with a smirk.
"Wha...?" You looked back to Asahi who was bashfully smiling with two pork buns in his hands.
"I payed for them in advance this morning!" Asahi had a slight blush dancing on his cheeks.
"ASAHI WHY DO YOU DO THIS TO ME?! YOU KNOW I HATE YOU BUYING ME STUFF!" You screeched and almost threw the nearest object at him until someone entered the store.
"Hey Kageyama!" You welcomed your volleyball friend and put down your object, which happened to be a radio.
"Hello (Y/N). Asahi." Kageyama nodded a hello in your direction and Asahi's. "Coach why weren't you at practice today?"
"I had to take care of the store because my brother got sick. I'll be there tomorrow though, Im calling in a friend." Ukai answered blowing out cigarette smoke.
"Oh...I hope he feels better." You sympathized for Ukai's brother.
"(Y/N) lets get going. I...I don't want to stay out too late." Asahi said heading for the door.
"Aww I forgot my lovely friend is afraid of the awful monsters in the dark!" You teased following Asahi.
"(Y/N)!" You looked to your nervous friend to see a bright red blush taking over his face out of embarrassment.
"Cya later guys!" You smiled and waved a goodbye.
"Cya tomorrow (Y/N)." You heard Kageyama say. You thought you saw his face turn sadistic. Evil. Vile. You being yourself brushed it off though. 
Asahi walked you home as he always did. He was so kind to you.
"(Y/N). Can I say something?" Asahi suddenly asked.
"Yeah go ahead."
"W-well. We've been best friends for a real long time. A-and I've always enjoyed our time together. I...I even talked t-to the team about it! So...will you do me the honors of....being my girlfriend?" You didn't know what to do. You were so flattered! His adorable confession touched you so much!
"Yes." You said without thinking.
"Wha-"
"Yes yes yes!" You said hugging him. However, Asahi pulled away and planted a soft kiss on your lips. Suddenly Asahi cried in pain.
"Asahi! Are yo- Oh my god. Oh my god Asahi!" You looked at his stomach which had a knife through it and blood everywhere.
"(Y-Y/N)..." Asahi slowly stuttered. However, in a few short seconds life drained from your boyfriends eyes. You broke down into tears right then and there. Tears streaming down your face and clouding your vision leaving you vulnerable to the attacker. Then everything went black.
~•~• End of very long flashback :( •~•~
You wake up stuck in your prison. Or as that bastard likes to say, your home. You were miserable. So miserable. You were running out of reasons to live. The entire volleyball team was dead. Each lifeless body had been burned into your memory as he brought their corpses to you one by one as a prize.
October 13 2016
Two long and suffering years after the tragic day
October 13 2016
The day you will be relieved
October 13 2016
The day you plan to die
You heard a knock on the door, but it opened with no hesitation.
"We're leaving." Your kidnapper stated. Kageyama stated.
"What day is it today?" You asked blankly.
"October 13."

(To be continued...)
A/N: Hey everyone! This is your result of Kageyama being yandere...Im gonna be so honest right now I was crying because I killed Asahi. My little tiny teddy bear...I am so sorry I killed him guys I feel bad. The next yandere I don't know...maybe Tsukki so I can do all the first years, second years, and then third years. Or maybe two at a time from each year? I don't know. Im gonna be so afraid to do Yamaguchi's yandere side because I am freaking Yamaguchi TRASH. Same with my Suga oh my god. Theirs are gonna be EVIL. But for now I hope you all enjoyed! Requests are up by the way, but I may not get to them until each Karasuno cutie has one chapter. For now though, I'll see you guys next time. STAY AWESOME!!