An Assassin's Rival (Haikyuu Assassin AU)

Chapter 1

"O-Oikawa," Kageyama choked out. His opponent had pinned him to a wall.

"Kageyama... It's good to see you again," Oikawa smirked.

"How's the manager doing?"

Kageyama scowled. "Why do you care?"

Oikawa chuckled almost evilly. "Kageyama, don't be so rude. Just because I left you guys doesn't mean I don't want to catch up every once in a while," he smirked.

"Neither of us ever wanted to see you again," Kageyama growled.

Oikawa released his hand from around Kageyama's neck and took a step back, but he cornered Kageyama so he couldn't move. "No, you just didn't want me around because I've always been better."

"Shut up," he snapped.

Kageyama and Oikawa stared each other down, neither taking their eyes off of each other's.

...Until someone interrupted their staring contest.

"Oikawa, what the hell are you doing?"

Oikawa immediately turned around, completely forgetting about Kageyama.

"Ah, Iwa-chan!" Oikawa stuttered.

Kageyama observed the situation as it unfolded, staying in the background as his rival and the newcomer argued.

"Oikawa, what the hell, running off like that?"

"Ah, I'm sorry, Iwa-chan! This guy is Kageyama, my rival! We had the same manager," Oikawa explained.

"Who?"

By this time, Kageyama had slipped onto the roof of the building above and disappeared from sight.

"Ah, he got away!" Oikawa pouted.

Iwaizumi rolled his eyes. "So now there's another assassin around?"

"No. He was just here on a mission," he explained. "But," Oikawa said evilly, "I think I know where he goes back to."

"Idiot, let's go get dinner. I don't care about your assassin friend."

"He's not my friend!"

...

Kageyama laid low for the rest of the day and carried out his mission the same night so he could escape before Oikawa found him again. Although he hated to admit it, Oikawa was the better assassin. And Kageyama knew he would be in trouble if he encountered him again.

Kageyama just wanted to see Hinata again, and get his mind off of his old companion. His old companion... Oikawa Tooru. They used to work under the same manager, as a team. Kageyama almost missed the days when he and Oikawa carried out missions together. They used to make a really good team. They used to get their jobs done incredibly fast and with incredible precision. Kageyama shook his head, trying to stop thinking about his former partner.

But who was that? Iwa-chan, was it? Kageyama could easily tell he wasn't an assassin just by what he said to Oikawa. But then, who was he? Oikawa's friend, maybe? A classmate? But Oikawa must trust him deeply if he told this guy that he was an assassin.

Kageyama thought about this the entire way back to his apartment. Of course, he stopped by Hinata's first.

He knocked on the door, waiting for Hinata to open it. When the door opened a few seconds later, it was Natsu.

"Ah, Kageyama! You're back!" she said happily. "Hinata is doing homework in his room."

"Oh, okay," Kageyama said.

"Where did you travel to this time?" she asked.

"Oh, I went to this really cool town. It was full of cool people and shops," Kageyama said, trying to interest the little girl.

"Really?" she asked. "That's so cool!"

Kageyama chuckled. Luckily, Hinata's mother called Natsu to the kitchen and Kageyama could slip upstairs.

Kageyama quietly found his way upstairs. He opened Hinata's door slowly, expecting to see him slacking off. Kageyama knew he wasn't the type to do homework for more than ten minutes at a time. But surprisingly, Hinata was sitting in his desk, focusing on his math homework. He didn't even notice Kageyama walk in.

Kageyama snuck up behind Hinata. "Guess who's back?"

Hinata immediately brightened up. "Kageyama!"

Hinata turned around and almost tackled Kageyama to the ground when he tried to hug him. Kageyama chuckled.

"You took forever!"

"I'm sorry. But I'm back now."

"Hmph," Hinata puffed. "Did anything happen? You're usually back a day early."

Kageyama wasn't sure whether he should tell Hinata about Oikawa yet. Deciding it was best to not tell him about the danger Oikawa might bring, he said, "no. Just took a little while longer than usual."

...

Kageyama woke up to the sound of his alarm clock. Groaning, he raised up to turn it off. He got out of bed slowly and sleepily changed and got ready for school. Yawning, he left his apartment and started on the road to school.

He walked for a while with his hands in his pockets, humming to the song playing through his earbuds.

As he got closer to school, he saw Hinata walking ahead. With a swift step, Kageyama had basically teleported right next to Hinata due to how fast he was.

"You didn't wait up for me," Kageyama said.

"Ah, sorry! Mom wanted me to take Natsu to school early for some project she has to prepare for. But then one of her friends caught up to us and Natsu went with her," Hinata explained.

"Mhmm," Kageyama said, not buying Hinata's excuse.

"I'm not lying!"

Kageyama laughed. "I'm just kidding, calm down."

As Hinata skipped a few steps ahead, Kageyama debated whether he should keep Oikawa a secret. His rival was definitely a danger, and Kageyama didn't want to scare Hinata. But what if Oikawa decided to come challenge Kageyama? Then it would be better if Hinata knew.

"Kageyama, what are you spacing out for?"

"Hmm?" Kageyama said, snapping back to reality. "Oh, just thinking."

"About what?"

Kageyama sighed. He should just tell Hinata about Oikawa.

"I should tell you something. Something from my past."