Haikyuu!! x Reader

Dating the Enemy {Oikawa Tooru} (Request)

You're dating oiks but it just so happens that you're his worst enemy's younger sister...
Requested by @yeanneelorejuan
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You frantically wrote numbers down on the giant whiteboard in front of you as each member of the Shiratorizawa volleyball team yelled them out at you. Keeping track of serving, passing, and hitting stats during practices was definitely your least favorite job as a manager of the team. You preferred to be initiating volleyballs to the guys while their coach examined them rather than being shouted at and being completely responsible for the accuracy of their hitting, passing, and serving percentages.

Once the drills had ended, you wiped a droplet of nervous sweat from your forehead before counting up the numbers and doing some simple calculations while the team took a water break. Immediately after they'd gotten water, they rushed over to you to bug you about their stats, but the coach stopped them and told them not to harass you. It was pointless, anyway, since they all knew well enough that your brother had the highest hitting percentage.

As their coach chatted with them about their practice, you noticed a figure appear in the doorway of the gym and wave to you through the net covering the entrance. You bit your lip to hold back a smile once you realized your boyfriend had come to pick you up after practice, despite the fact that it was a little out of his way.

Ushijima noticed the slight blush on your face and the fact that your attention was directed somewhere other than the coach, and he felt his blood boil slightly. He didn't even have to turn around to know that his least favorite person was on the receiving end of your loving gaze. Oikawa's nearby presence usually didn't have much of an effect on him, but it only bothered him now that his younger sister was romantically involved with him.

After the meeting, the coach ended practice and thanked you for all of your help. He then proceeded to look at the team's stats and copy them down into his notebook, relieving you of any further duties. Feeling a rush of joy hit you, you ran and grabbed your school bag before sprinting over to the doorway, pushing the net aside, and jumping onto Oikawa.

"Hey, (f/n)-chan! I'm so happy to see you!" he greeted you happily as he wrapped his arms around you tightly and smiled down at you.

"I missed you so much!" you told him, taking a moment to experience his familiar warmth and comfort that you hadn't gotten to feel for about a week and a half. He'd been so busy with school and volleyball that he hadn't been able to come and see you for what felt like such a long period of time. So, now that he was back, you were going to appreciate being around him again and getting to spend time with him.

The two of you exchanged long greeting kisses that, unfortunately, were soon interrupted when someone cleared their throat nearby. You broke away from one another and looked over at Ushijima, who was watching you both with a look of dissatisfaction. "Oikawa."

Oikawa frowned and placed his free hand on his hip. "Ushiwaka-chan."

"Don't call me that."

"Don't tell me what to do."

"What are you doing here anyway?"

"I'm here to see your lovely sister, who just so happens to be my girlfriend."

Ushijima grunted in return, since he couldn't necessarily argue with him there. As much as he hated it, you were dating his rival. "Come on, (f/n), let's go," he grumbled.

There was a long and painful silence as the three of you walked back to yours and Ushijima's house. Oikawa held your hand as he walked on your left side while Ushijima walked on your right side. You were the only thing getting in between them and strangling each other at the moment and it made you very uncomfortable.

When the three of you arrived at your house, you rushed upstairs to pack your duffel bag, since you planned to stay the night at Oikawa's house like the two of you had planned. The only catch was that your brother didn't know that yet.

Once you'd finished packing, you returned downstairs to find your brother and your boyfriend up in each other's faces, growling at one another in a heated debate.

"Why are you still sticking around, Oikawa?" Ushijima questioned angrily, "Go back to the dumpster you crawled out of."

"I can assure you that if I did live in a dumpster, I wouldn't offer to have your sister stay over, Ushiwaka-chan," Oikawa shot back.

A look of confusion came over Ushijima's face, and he looked over at you, his olive eyes moving from your duffel bag to your own eyes. It was like his worst nightmare coming to life. While you'd been over to Oikawa's house many a time before, you'd never stayed the night there.

"(F/n)... are you really staying with him?"

"It's just one night, Wakatoshi. I'll be fine," you attempted to assure him as you walked over to Oikawa and stood next to him.

"I don't trust him."

You were about to open your mouth to defend your boyfriend, but Oikawa stopped you by putting his hand on your shoulder. You watched him as he took a deep breath and stared firmly at your brother with his brown eyes.

"I know you don't like me to begin with, and I know that you hate me because I'm dating your sister, but, in all honesty, there's no reason why you shouldn't be able to trust me. I've been with her for a long time and I've always returned her home safely whenever she's come over to see me. I sit with her on the train ride there to make sure nothing happens to her, I ride with her on the train back to make sure she's safe at night, and I walk her all the way back home so I can protect her and see that she gets back safely. While the two of us may be rivals, Ushiwaka-chan, there's no reason why you should let that affect mine and (f/n)-chan's relationship. You never have to doubt her safety when she's with me. As much as you and I don't like each other, we have to put our rivalry to the side for your sister's sake because I love her and that isn't going to change no matter what."

A long silence followed Oikawa's confession as Ushijima watched him carefully and you admired him. Oikawa took his hand off your shoulder and allowed your brother to pull you into a hug. When he released you, you put your arm around Oikawa's back.

"If you hurt her, I'll break every bone in your body," Ushijima threatened quietly.

"I would never," Oikawa responded diligently, pulling you closer to him and rubbing your shoulder, "I'll bring her back safely, as always."

You could tell Ushijima wanted to keep you, but he restrained himself and let you walk away with Oikawa after saying your goodbyes. He watched as you and Oikawa talked happily, exchanging kisses from time to time. As much as he wanted to oppose your relationship with him, Ushijima couldn't deny that he made you happy, so he wasn't going to intervene.