Hello there! So I finished both the anime and manga of Haikyuu and Diamond no Ace and I'm in need of some crossovers of these awesome anime! I just thought of this during my spare time and was itching to write it and want to share it to those who are in need of the crossovers between HQ and DnA.

To those who didn't get to read the manga of Haikyuu, there's going to be MAJOR SPOILERS below so unless you don't want to get spoiled, don't read my story or read the manga to know more! ^^

Hope you guys enjoy.

Chapter 1: Invitation

It was the usual day at Seidou: practice in the morning and night and doing some batting and pitching drills. Tonight, I was having the usual pitching drills with Miyuki-senpai. It was always a thrill as I throw the ball towards his mitt and he catches it with ease. I just can't help but continue improving my pitch so long as he's around.

"All right. That's it for today, Sawamura!" Miyuki stood up as he was about to remove his protective gear, a sign that we're really stopping.

"What the? But I've only pitched 50 so far!" I jumped and demanded for more pitches. It's not enough!

"Exactly" he said matter-of-fact as he place the protective gears in the storage room "We have a game against one of the powerhouse in Osaka in three days. You need to rest and be in top shape by then as you'll be the starting pitcher."

"Geh! But it's still so far away. Boss won't let me pitch tomorrow and told me to have a day off after all." I stared at him like a child wanting to stay at the mall or at a park. I just want to spend more time with him, as a pitcher to a catcher of course. Can't he understand I want to practice my form with him?

"That's because you pitched the whole 9 innings today during one of our scrimmages with another team." He sighed, as if telling me he's annoyed at something. Certainly not to me. "You should take it easy," he smiled teasingly as he walk passed me "It's not everyday you get a day off and we get to go on a mini trip with the team. Zono's pretty excited to see some old friends since he's from Osaka."

"No! Let me pitch!" I grabbed his leg before he could run off. I just want him to catch for me just a little bit more. The game is still far away and I have to wait till we go to Osaka. To-

"Wait, Osaka?" I said it at the same time I was thinking it. I stopped what I was doing and looked up to see Miyuki, who was struggling to keep his balance. I stared at him for a quick second.

"Y-yes in Osaka!" He tumbled and fell as I released him. "Didn't you listen to the coach during our meeting a while ago?" I helped him up as I laughed.

"Well, I was distracted" 'because I want to pitch with you after the meeting' I thought but good thing I didn't say it. Knowing him, he'll just laugh it off. "But Osaka huh? Where exactly in Osaka?"

"I think it was near the city district of Ohasuhigashi in Higashiosaka."

I grinned. Perfect. Just absolutely perfect. I can't wait. But Miyuki is right, I should rest up and be at my top shape. I can't wait to show my skills to them. They'll make fun of me if I screwed up. I just know it.

"Osaka huh? Well, I guess I can't say no to the Cap and the Boss when you guys tell me to rest. Sorry for dragging you here, Cap! Here, I'll clean up." He stared at me with a worried look all of a sudden. I was about to ask what's wrong with him until he gave me one of his snarky remarks in which I replied with annoyance.

After our shared banter with one another, we went in our separate ways as we headed out in the practice building. He told me he's meeting with the other senpais at the dinning area.

"Alright. Thanks again Miyuki-paisen!" I waved as he turned his back on me, waving me back. I stood there as he slowly disappear and I gave a heavy sigh. That idiot. He's very good at analyzing stuff in a game and in baseball but doesn't realize anything at all. Oh well. We all came here to play baseball afterall. No need to hold on to these kinds of feelings as we're too busy training to go to the Nationals this summer and he's the captain and the clean-up. Feelings like love is probably the least of his concern. I guess that goes the same for me... Welp, no use in being sad about this. I got to put my head in the game. I should relax tomorrow like he said. Which reminds me, I got to text him first. I can't wait to tell him that I'm going to Osaka. Just when I was about to open my phone, a message popped out. I read its contents and laughed for the coincidence and the timing.

From: Hinata Shoyo

Eijun! I forgot to tell you that I'm here in Tokyo with the rest of the team ^^ We have a match against Kageyama's team tomorrow and I was wondering if you want to watch the game? But if you have practice, it's okay but it wouldn't hurt to ask afterall. Everyone's excited to see you though and yes, I'm making you feel guilty :P Just kidding! Hope to hear from you Eijun! :D

PS. Bokuto-san's excited to see you as well (not a blackmail)
Atsumu-san said Osamu-san made special onigiris for you and for the team (swear it's not a blackmail for you to say yes)
Omi-san is still Omi-san

For once, I'm thankful that I actually have a day off tomorrow.

Hinata Shoyo. A pro-volleyball player and one of the people I looked up to but Chris-senpai will always be my number 1. He's like a brother to me. It was my 11th summer when I met him. I visited my cousin, Daichi, back in his hometown in Miyagi and I used to be clingy towards Daichi-nii so much so that I ended up following him to his school and when he was at his volleyball practice. I met everyone in his team and luckily they let me in the gym whenever they practice. I heard they lost in the Inter-high and some of the players were still affected by it. I looked at some of their members and saw an orange-haired short guy tossing the ball over and over again by himself. I asked Daichi-nii what on earth is he doing by himself and Daichi smiled and pat my head and said,

"He's doing his best. Both for him and for the team." He gave me that reassuring smile, believing in his beloved kouhai. Daichii-nii's so cool!

At that time I was confused but now that I'm older and at the same age Shoyo-san was at that time, I understood it all. I really do.

Over my summer days when I was 11, I tagged along with the rest of the Karasuno Team when they went to Tokyo for their training camp. And by tagged along, I mean secretly hiding myself in the bus. There was quite a fuss back then and Daichi-nii hit me and he was always scary whenever he's mad. During the training camp, I get to bond with the rest of the Karasuno Team and with the other teams as well. But the ones I get to know most were Tobio-san and Shoyo-san. I remembered they fought back when they got back from the training camp but soon made up afterwards. I watched them play volleyball and I was always in awe with how Shoyou-san plays volleyball. As if he could fly with all his might and the look on his eyes whenever Tobio-san sets the ball for him was always entertaining to watch. During those times, the team taught me how to play too whenever they're free. Daichi-nii and Yuu-san taught me how to receive the ball and locate its position, Kou-san and Tobio-san taught me how to set (which was a bit hard for me because I'm too impatient), while the rest taught me how to spike and block- which I enjoyed the most. The scary coach and their advisor was fun to be with, though I was a bit scared at Ukai-san at first. Kiyoko-san and Yacchan were always there to watch over me too and I enjoyed their company. The team was so welcoming to me that they even told me I'm so good in volleyball just to make myself feel good at that time.

Back then, I enjoyed playing volleyball, even joined a team when I got back in my hometown and apparently made a name for myself but I don't want to remember about that. However, when I borrowed a friend's manga and read about Baseball, I suddenly took more interest of it. I stopped going into volleyball practice and I started practicing how to pitch. In the end, I chose Baseball over Volleyball and I felt so guilty that I told it to Shoyo-san the second year I went back to Miyagi to visit Daichi-nii's family. I went to their gym and it seems like they're happy whenever I'm there even though Daichi-nii, Kou-san and Asahi-san already graduated.

"You don't have to cry about it Eijun!" Shoyo-san smiled and comforted me. They had a break and we were sitting right in front of the entrance of the gym. "We taught you how to play because you were curious."

"W-wrelly?" I couldn't say the proper words as tears and snot were all over my face.

"Yep! Though it's a shame because you seem to have a knack for volleyball but I could see it in your eyes that your heart is set in baseball and we'll always support you Eijun. Sports is meant to be free afterall." Shoyo-san gave me his warmest smile as always. I always see him as a big brother whom I could always look up to. He knows his weaknesses but that doesn't stop him from being one of the most feared players in the prefecture and that's already awesome of him.

"S-shoyo-san! I wuuuuv you!" I cried louder and hugged him as he pat my back.

"Oi, Eijun. You should stop crying and hugging the idiot. You could catch his stupidity," Tobio-san grabbed me from behind "Whoops. Maybe I'm too late?" Tobio-san teased as he quickly glanced to Shoyo-san.

"What did you say Kageyama?" Shoyo-san stood up and glared at him. I was between them as they both glared at one another.

"Now now, you guys should stop it. We were supposed to comfort lil Ei-kun." Tadashii-san attempted to pacify the situation and took me out between them.

"Don't mind them Eijun," Kei-san appeared as he was cleaning his glasses "that idiot king is just frustrated over the fact that Hinata's going to Brazil when he graduates."

"You idiot!" Everyone on the team all grabbed Kei-san to hush him. Almost everyone needs to tiptoe to grab his mouth because that boy is tall as heck. Yuu-san managed to do so when he lounge at Kei-san's stomach.

"Shoyo-san's going to Brazil? Where is that?" I asked curiously. Everyone was all eyeing on Kei-san who just put his arms in the air and walked off.

"Uhh well Eijun-kun it's at the other side of the world but don't worry. It's still in a few years." Yacchan slowly explained it to me and I cried again, much harder than earlier. Everyone punished Kei-san by letting him buy us buns and all was forgiven.

When the time that Shoyo-san went to Brazil, we exchanged emails. I watched his games via the internet or sometimes in the television. Tobio-san ended up going pro after graduation and I would watch his games online too. I get to know their friends and teammates too. When Shoyo-san came back, I was already in Seidou and he invited me to watch his first official match and it's against Tobio-san's team but I told him I can't since I was training my butt off to be the ace. He laughed and told me that he was also like that when he was in my age and gave me encouraging words and that made me more pumped up than usual. I watched the recap after practice though and I cried when Shoyo-san made an outstanding receive from none other than the Waka-sama, heck I bet that was his best receive yet. Would've been nice if I was there to meet with the others but now that I have the opportunity to finally watch them tomorrow, I must not let it go to waste.

I decided to call him instead, feeling excited. After two rings, he answered.

"Shoyou-san! It's been a while. You're finally here huh?" My excitement could be heard from the tone of my voice, even I noticed it.

"Hi there Eijun! So? Will you-!" Shoyou-san was cut short as I could hear his voice slowly becoming distant. Someone must've taken his phone from him. I heard him shouting from the background.

"Eijun? Eijun? Junei? Heyya Junei! It's been sooooo long! Will you be there tomorrow? Of course you will." A rather energetic voice suddenly appeared behind the line.

"Kotarou-san!" I smiled. As Shoyo-san is like a brother to me, Bokuto-san is like that awesome ride-or-die kind of brother and he and I usually see eye to eye.

"Ehhh? Eijun-kun?" Another voice joined in "Hey there, Lil Eijun-kun. Listen, Samu said he'll prepare some onigiris for you if you come and watch us tomorrow."

"Woah that's really great Atsu-san! You guys really don't have to." I laughed as I'm so looking forward to Osamu-san's onigiris. I've heard they're good and his restaurant was even featured in the news.

"Hey! Omi-omi! Eijun-kun is here. Come say hi!" Atsu-san shouted and I heard someone grunt as he got closer to the phone.

"Why would you let me use something that's been used by a lot of people, Atsumu?" a rather uninterested person came in as if he had no choice.

"Hey Atsumu-san! That's my phone. Don't you guys go stealing someone's phone when they're talking to someone. And Sakusa-san, please don't treat my phone as if it's a virus itself." I could hear Shoyo-san's voice from afar behind the line. Looks like he managed to catch up with them. I could tell they're making fun of him. Those guys were always fun to be with even back then.

"Do you have any idea how much bacteria has been accumulated already just by Atsumu holding it alone?" Omi-omi said as if it was a fact.
"Eh? Why are you treating me as if I'm a bacteria?"
"That's because you are one."
"Guys enough and give me back my phone!"
"Tsum-tsum the King of Bacteria!"
"Shut yer trap there Bokuto!"

"Uh guys? I'm still here you know." I interrupted them. Seriously whenever these four are together, it's never a dull moment. I want to be there with the awesome four-horsemen of the MSBY Jackals!

"Oh right. Sawamura-kun, huh? I'll talk to him but put it on speakers. No way in hell will I let that thing be placed on my face." Omi-omi-san strictly instructed Atsu-san. I could hear Atsu-san chuckled as he agreed.

"Hello there Sawamura-kun" Omi-omi-san greeted straightly "I heard you're in Tokyo. Will you come and watch our game tomorrow?"

"Salutations good sir Omi-omi-san!" I saluted, imagining that he's in front of me. "I will go and ask permission first to the Boss if he's okay with it. I'll text Shoyo-san afterwards."

"B-boss? Is he some sort in a gang perhaps?" Atsu-san laughed.

"Boss! That's so freaking cool. I wonder if we could call coach Samson boss too? or Master? Wait even better! The great master boss!" Bokuto-san cheerfully said. I could hear Shoyo-san agreeing in the background and Atsu-san telling them to stop it.

"Okay Eijun. Tell your 'boss' that we'll give him tons of souvenirs plus some onigiris for the team. I heard you've been doing well in your practice games lately. I'll wait for your text. We got to got now. We're about to have a meeting." Shoyo-san quickly grabbed his phone away from the others. "Say goodbye to Eijun now everyone!"

"So long Sawamura-kun."
"See you soon Eijun-kun!"
"Junei byebye!"

*click*

"YOSH! TIME TO HEAD TO THE HEADQUARTERS AND TALK TO THE BOSS!" I yelled excitingly. I swear I could hear someone scolding me from afar but maybe it's just my imagination as I head to the office.

It wasn't till long when I reached the office. Almost everyone is out either practicing or having dinner by now so this is rather a good time to talk to the boss. I knocked at the door.

"Good evening sir. Tis I, Sawamura Eijun! Requesting an audience with the boss, himself." There was silence at first and then a sigh behind the door.

I waited or a couple of seconds before I was told to get in. When I went in, I saw the four of them: Boss, Little Boss, the president, and Takashima-sensei. I grinned and bowed at them.

"Good evening Maam and sirs!" I saluted and continued, "I am aware that I am not allowed to pitch tomorrow and added to that it's my day off in preparation for our game in Osaka. I just want to give a heads up that I'll go out somewhere tomorrow because I will watch my friends's match. I'll be back in the dorms by late afternoon."

Boss was quiet and nodded. "Very well. Make sure you condition yourself well. It'll be good for you to just relax for once after you've gave us a good 9 inning game a while ago."

"R-really boss? I was good? Well, I sure as heck won't disappoint you in giving my all to rest tomorrow! In fact, I could pitch all night long today so that I could fully rest tomorrow." I jokingly said as I started stretching my left arm. It always feels good to be recognized one's hardwork and by Boss nonetheless!

"No." He demanded and I just grinned. I excused myself from them as I was excited to tell Shoyo-san the news. As I was about to head out, Takashima-sensei asked me if it's someone's baseball game practice that I'll attend and if so, she wants to join too.

"Nope! It's not a baseball game, would be cool though" I smiled and thought of Shoyo-san and them playing baseball. With the way he spikes, he'd make a good pitcher though "the one I'm going to watch is a volleyball game match between the monster generation of volleyball." Takashima-sensei and the others in the room were confused as I closed the door. As I head down the stairs, I texted Shoyo-san.

From: Hinata Shoyou

YAAAY! Bokuto-san did a headstand when I told him you'll come and watch us tomorrow! :D A car will come and pick you up tomorrow at 7 am. Be ready by then. See you tomorrow!

'Eh? Why is it so early?!' I replied. Is it really that early if you're a pro? Damn. The world of pros is scary afterall.

"It's a surprise. Gtg now! We're still doing some preparations here for tomorrow."

I texted him good night and chuckled, he sounded like he was in a hurry. I can't wait to see both Shoyo-san and Tobio-san tomorrow. That reminds me. I should text Tobio-san about me going tomorrow! Just as I was about to text him, a message popped out and it was from him. Geez, he and Shoyo-san are always thinking alike huh?

From: Kageyama Tobio

Good evening Eijun. The Adlers have a game match between the MSBY Jackals here in Tokyo and your high school is near in the arena that we'll be playing at. Would you like to watch me defeat the idiot's team tomorrow? I could reserve a seat for you right in front of the court if you'd like.

To: Kageyama Tobio

Hello there Tobio-san! Shoyo-san told me about it already! And yes I'll come and watch you guys tomorrow. I wish you both the best of luck.

From: Kageyama Tobio

Tchh. That idiot beat me first to you huh? Well that doesn't matter. My team is going to be yours tomorrow. Prepare yourself Eijun. Good night.

To: Kageyama Tobio

Yes! I look forward to your match as well Tobio-san. Good night.

I got a feeling Tobio-san is calling Shoyo-san right after we text. I just know it since Tobio-san doesn't want to be one step last to Shoyo-san after all. But something's weird. He said that he's going to defeat us? What does that mean?

"NOICE. I CAN'T WAIT FOR TOMORROW!" I roared as I decided to go for some runs before going to bed. I'm too excited after all. During the run, I can't help but wonder why I should be early tomorrow or the fact that Tobio-san wants to defeat us, with me included. I'm probably just overthinking it. Looking forward to tomorrow though.