Disclaimer: I do not own Prince of Tennis. I only own my love for Kaidoh Kaoru-sama!

A/N: A birthday fic for one of my favorite characters, Sadaharu Inui. Unimplied shounen-ai, but you can scratch off the "un" if you wish. XD Tanjoubi Omedetou, Inui-san! /cheers/ Btw, Fujiko-chan (mentioned in this story) is Eiji's pet name for Fuji in the anime.

Shiranai no Tanjoubi
by Immortelle Stalker

The soft morning breeze felt nice with the warmth from the sun as Kaidoh jogged towards Seigaku. He gripped on the strap of his tennis bag and lessened his pace upon entering the school campus. When he got to the locker room, Kachiro and Katsuo were inside, along with Fuji and Kikumaru. "Ahh, ohayou Kaidoh-senpai!" Kachiro greeted as he heaved up the basket of tennis balls. Kaidoh simply hissed and walked past the two. Though it looked mean, that was just the way Kaidoh greeted people. The junior settled his bag on the floor and took out his tennis racket. While doing so, he overheard Fuji and Kikumaru talking

"Nee nee, it's Inui's birthday today right?" Kikumaru said to Fuji. Kaidoh's ear seemed to have twitched upon hearing that. He cocked his head slightly to the side to listen. "Maybe," was Fuji's brief response. "Eeh? You don't know, Fujiko-chan?" Kikumaru exclaimed in disbelief. Kaidoh was in a surprised state as well. Though he trained with Inui, he didn't even bother asking about personal things like that.

"Well, you remember what happened when we're still in our second year, right?" Fuji said. Kikumaru nodded. "We originally thought Inui's birthday was October 23, since that was written in his records," Kikumaru nodded again, this time with his usual catchphrase, "Nyaa." Fuji led out a soft chuckle and placed his hand below his chin. "There was even the time when he told us that he was born on February 30."

"There isn't even a February 30,"

Kaidoh almost jumped up in surprise when he accidentally said that out loud. Fuji and Kikumaru both turned to him, and it made the sophomore mentally curse himself for eavesdropping. Kikumaru laughed and faced Kaidoh. "Hai! That's exactly what Fuji said! Fuji should know since he's a leap year baby, nee Fujiko-chan?!" He then turned to Fuji, who nodded with a giggle.

"Oh," was all Kaidoh could say at that. Kikumaru then approached Kaidoh and stooped down with him. "Nee, you trained with Inui, right? Do you know?" Kaidoh moved back a little. "Uhh... I haven't really asked him about that." Kikumaru then hushed out an 'I-give-up' breath and stood up, placing his hands behind his head. "Hmm... Inui's really a serious guy."

"Seems so," Fuji said with a smile. The two then left the locker room, leaving Kaidoh alone inside. "Birthday... eh?"

All throughout practice, Kaidoh observed Inui from afar and looked out for any hints of delight. Most people are happy when their birthday comes, right? Maybe he could catch even a slight difference in Inui's mood if he observe carefully. Kaidoh looked away for a moment to tighten the knot of his bandana. When he looked back, Inui was not there anymore. "Eh?"

"Is there something you want to talk to me about, Kaidoh?" Inui spoke from behind Kaidoh. The kouhai almost jumped a mile high due to shock. Inui had that all-knowing smirk in his face, meaning that he had noticed Kaidoh glancing at him for a while already.

Kaidoh couldn't find the words to explain himself. Lucky for him, Ryuzaki-sensei called everyone to gather. He was safe to think up an excuse, for now. As Ryuzaki-sensei talked, only a quarter of the boy's consciousness actually listened. He wanted to pay back the training that Inui gave him somehow, but didn't know how he could. So, if it really was Inui's birthday, then maybe he could do something. Wait... What if his twisted sadist side comes out? What would become of me then?! Thoughts of new and 'improved' Inui Juices flooded in, choking Kaidoh's mind. Oh, even the thought of Inui Juice sent unspeakable horror through the boy's spine.

"Kaidoh!" The spaced-out sophomore snapped back to actuality when Ryuzaki-sensei called his name. "I'm going to repeat what I said. I'm dismissing you early today!" Kaidoh blinked, then looked around. All of the players had already scattered, leaving him the only one still in line. "Uh, hai! Arigatou gozaimasu!" The mortified boy bowed down and quickly dashed away from the scene. He completely forgot about Inui's confrontation, which was good in a way since he hadn't really thought of something to explain himself yet.

When Kaidoh got home, he went straight to him room, dropped his bag on the floor and motioned towards the window. Though Inui told misleading dates to everyone, Kaidoh got that feeling inside him; it might be worth a shot if he returned the favor that day. So, he changed his clothes and went out to pay Inui a visit.

It took Kaidoh a while to get to his senpai's home. He had only been there a couple of times, if he remembered correctly. Inui usually went straight home to work on his computer during early dismissals, so he might be there already. Kaidoh reached for the doorbell, his mind debating whether to ring it or not. Eventually, his mind agreed to proceed. After five seconds, Kaidoh hushed out an annoyed hiss. He might be out collecting data...

The door swung open as Inui emerged from behind it. "Kaidoh?" The kouhai blinked, then bowed down. "I need to have a word with you, senpai." Inui cocked his head to one side. He wondered why Kaidoh seemed interested at him since practice, but the probability of him actually paying him a visit was slim. "Very well, come in." He led his kouhai into the house and towards the living room. Kaidoh looked around as he took small steps. It seemed like Inui was alone, as usual. In fact, during the times that he had been there, no one else were with him.

Inui sat down on an easy chair while Kaidoh settled on the couch. The data collected kept his silence, which made Kaidoh a bit nervous, but he swallowed his uneasiness and spoke up first. "I-I was just thinki—" His sentence was cut short when he heard something explode from one of the rooms. It wasn't that loud, but it was surprising. "W-What was that?!" Kaidoh exclaimed as he looked at the direction where the explosion came from, Inui's room. From the corner of his eye, he saw Inui adjust his glasses while looking at the notebook in hand. "Hmm... I seem to be having trouble with the amount of ingredients in the mixture. That's the third explosion since I came home."

Kaidoh felt the blood drain from his face. That might be another Inui Juice in the making, and he was perfectly available to be the first taster. What have I gotten myself into? He turned to Inui completely, who was writing something on his notebook. "Please excuse me for a while, Kaidoh. I'll just do a little adjustment with my experiment." Inui got up and went to his room. Kaidoh waited without moving a muscle, thinking if he should get on with his idea. You fool! You're here already, so just get on with it! It's for Inui-senpai! The boy gulped, stood up and walked towards Inui's room. Slowly, he peered into the open door. Inui was sweeping away the remains of what used to be a beaker with a small brush. Then, he took a rag from the side and wiped the liquid off his desk. Kaidoh's eyes zeroed in on the glass of weird looking concoction sitting near the edge of the desk.

I-Inui Juice... looks more horrible than the last one... Kaidoh thought with a shiver. Then, his mind flew off when Inui accidentally knocked the glass off the table. The contents poured on the carpet below, corroding its surface. "W-wha-wha..." Kaidoh couldn't utter a simple word, and it placed too much pressure on his body. He scrambled towards the front door and yelled, "I am not drinking that!!"

"Kaidoh... Kaidoh?"

Kaidoh's eyes blinked multiple times, as if he just woke up from a daydream. He looked up to Inui, who stood in front of him. "What's wrong, Kaidoh?" Inui asked. Kaidoh took one last blink, looked at the door of Inui's room then shifted his eyes back on his position. He hadn't stood up or even approached Inui's room. Heh, I was just imagining stuff... The cracked junior chuckled in his mind. Maybe it wouldn't be bad if I think positively... He looked up to his senpai again with more confidence. "Senpai, I... I heard it's your birthday today!"

The obviously surprised Inui tilted his head to one side, a habit he had been doing since Kaidoh arrived. "Birthday? Kaidoh, where did you get—"

"Please let me accompany you today, senpai!" Kaidoh cut off as he bowed down in his seat. "I will pay you back for training me."

Inui glanced at his kouhai for a while. Then, he fixed his glasses and took out the notebook from behind his back. Inui would be incomplete without his little green notebook. "Oh? This is quite convenient," he replied. "I have a lot of things to do. Would you really like to accompany me, Kaidoh?" The younger boy nodded, making Inui grin a little and hush out, "Excellent."

Kaidoh gulped. There was always something about Inui's grin that made him regret his actions. But he decided to be a little more serious about his proposal. So when Inui told him to follow him into his room, he gathered all his courage and did what he was told. When he arrived at the room's doorstep, he saw the corroded carpet and the knocked-down glass on the table. N-No way... Kaidoh took stiff and nervous steps into the room, looking like a wind-up nutcracker.

"I am working on my assignment for Chemistry class," he heard Inui say. Kaidoh stopped, then faced Inui, who was arranging the beakers and test tubes on his table. "You can watch what happens with the mixtures. Then tell it to me so that I can do my calculations without intrusion. Is that okay with you, Kaidoh?"

"A-assignment?" Kaidoh hushed out. So, it was not Inui Juice. As long as it doesn't involve that horrid excuse for a health drink, then he wouldn't have to worry. "Hai... senpai," He got a stool and sat near the experiment and watched the chemicals fizzle and boil inside their containers. "You're having a hard time with this assignment, senpai?" He asked. Inui chuckled as he twirled the pen on his hand. "Well, even Sherlock Holmes nods. So, shall we start, then?" Kaidoh nodded.

It took them a couple of hours to finish the assignment. And when they did, Kaidoh stretched his arms and blinked his eyes. Inui jotted down some things on his notebook before doing his own stretching as well. "We're done. Thank you for your help, Kaidoh," the senior said. Kaidoh's eyes drooped as he blinked them again. "My eyes feel heavy. I think I stared too much," he confided to his senpai. Inui spun his chair to completely face Kaidoh. "Really? Then, would you like to accompany me further? I have this something I would like to see... It would also help relax your eyes." Kaidoh looked at his senpai and wondered what they would do next.

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"Senpai... Do you really want to see... this?" Kaidoh asked with a pale face.

"Yes. I would like to see everything." Inui's eyes gleamed as he nodded.

They were seated inside a movie house, waiting for the attraction to start. It would have been great for Kaidoh since the senpai generously paid for his ticket as well. But Kaidoh suspected that the sadistic Inui wanted to get more amusement out of his money. So, Inui pulled Kaidoh into a horror movie, even though he perfectly knew how Kaidoh easily gets scared of the supernatural, no matter how hard Kaidoh denied it.

"I've been planning on seeing this when I get a free day," Inui added with a smile on his face.

Kaidoh pouted his lower lip and led out a ffssshhhuu. He gripped on the arm rest when the movie started. Inui-senpai seems to be enjoying the movie. He's not even jotting down notes... Kaidoh thought while he tried to conceal his cowardice. His eyes widened when the ghost finally appeared in the movie. So, he closed his eyes shut, tried his best not to scream his lungs out and make a gutless fool out of himself. This is going to be a long movie...

"Kaidoh…" Inui said as he tugged Kaidoh's sleeve lightly. "I'm busy right now, Inui-senpai!" Kaidoh growled. He kept his eyes shut and curled in his seat. Yes, Kaidoh was indeed busy; busy trying not to see anything out of the ordinary. Yet, Inui kept on tugging his sleeve. Kaidoh gave in and finally turned to Inui. "What is— AAAAAHHHHHH!!!!" He jumped off his seat and quickly dashed out of the movie house in a blink of an eye.

The people seated near Inui all turned to look at him, and they too screamed their spirits out and ran away. "H-HIS FAAAACCEEE!!!" they yelled. Inui couldn't contain his calm chuckles as he removed the faceless mask from his face. "Well now. This exceeded my expectations. This was only for Kaidoh's amusement... The last yell sounded rude." He took out the notebook from his jacket and jotted down his notes. "Fuji does have great stuff in his possession."

Outside the movie house, Kaidoh slumped on the ground, his heart still raced from fear. "Calm down... It was clearly a psychological effect from the movie..." He whispered to himself.

"Kaidoh..." Inui finally went out of the movie house and approached the disorientated Kaidoh. The junior looked up Inui and quickly got to his feet. "I-I'm sorry, senpai. You had to skip the movie because of me," he muttered under his breath. Inui smiled and patted Kaidoh's shoulder. "It's okay. It's my second time to see the movie anyway."

Kaidoh's eyes flew up to Inui's face. "What?!" Inui smirked with his hands inside his jacket pocket. "This movie was so good that I had to see it for the second time. But I felt a bit bored, so I thought of trying out Fuji's faceless mask. See?" He took out the faceless mask from his pocket and showed it to Kaidoh.

"F-faceless mask?" Kaidoh stared at the object in Inui's hands. One second. Two second. "S-senpai…" The infuriated Kaidoh growled as he tried his best not to strangle the clearly amused Inui. The kouhai's suppression was obvious to Inui, and he didn't want to let his company go just like that. So, he motioned behind Kaidoh's back and pushed him forward. "Let's try to get some snack and then head back to my place. I am still feeling generous today."

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The two Seigaku regulars walked side by side along the sidewalk, but neither of them said anything since they left the convenience store. Kaidoh slightly bit his lip, still furious about Inui's idea of 'fun'. Heh, guess I should tolerate this... It's his birthday anyway. "Kaidoh," he heard Inui say. The younger boy looked up to Inui. "How did you know that it is my birthday today?" Inui asked. Kaidoh looked at his side, then to his front. "Kikumaru-senpai and Fuji-senpai were talking about it earlier in the locker room," he replied. Inui led out an enlightened hum and didn't say anything more until they made it back to his house.

Inside, the two settled on the living room and ate their snacks. Most of the time, Inui talked about Kaidoh's training schedule and gave him tips on how to improve his techniques. From the way his senpai talked, Kaidoh listened in awe and admiration. Though the only thing they talk about was tennis, it somehow made the younger boy feel that their personalities were alike. No one could connect with Kaidoh until Inui came.

"Oh, we should have bought more drinks," Inui said as he shook the empty can of soda in his hand. Kaidoh blinked, then looked at the other cans. They were so drowned in their talk that he didn't realize that the sodas were all gone. Inui slowly got to his feet. "I'm going to get something in the fridge." Kaidoh nodded as he watched his senpai leave the room. A short while later Inui came back with two containers in hand. "Here, this one is for you," he handed one container to Kaidoh.

"Ahh... domo," Kaidoh lowered his head and watched Inui drink from his own container. He did the same, but the moment he took in the drink, he completely froze. "I-Inui... senpai..."

"Yeah?" Inui uttered.

"W-what did I do to deserve Inui Juice?" the poor junior drank a sip of Inui Juice in spite of all his cautions.

Inui's lips curved up in a gleeful sadistic grin again. "Nothing. It's just that I'm out of water at the moment, and Inui Juice is the only thing available."

Kaidoh's eyebrows twitched, his face pale from the unpleasant taste of "The Juice". "S-sou... ka..." With that, Kaidoh dropped on the floor and passed out.

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He could feel a soft breeze touch his face, then the usual sounds that he heard around town. Kaidoh's eyes slowly opened and were welcomed by the complete view of the yellowish orange sky. "Where..." He hushed out. "Isn't the afternoon sky here nice?" Kaidoh turned to his side and saw Inui seated beside him. Gradually, Kaidoh sat up. "Careful," Inui said. "You might fall off." Kaidoh turned to see where they were exactly. They were on the roof for some reason. The junior then sat up more carefully and wondered how he got there with Inui. Clearly, he was knocked-out by Inui Juice downstairs, at Inui's living room.

"I carried you, of course," Inui replied out of the blue, as if he knew completely that Kaidoh would ask that any minute. Kaidoh looked at his senpai for a while, then he asked, "Senpai, is it really your birthday today?" Inui smiled, his eyes fixed on the setting sun in front of them. "Would you be angry if I say that it isn't?" he replied. There was a ninety-seven percent change that Kaidoh would yell in front of his face and a three percent chance that he would push him off the roof as payback for his sadistic rampage. But to his surprise, Kaidoh just led out a chuckle.

"So I guess I should just do this every year, hoping that it could finally coincide with your real birthday," Kaidoh replied, his face didn't show any sign of annoyance. "Thank you for today, senpai." If he wasn't with Inui, then he'd probably be off alone somewhere, as always.

Inui looked at Kaidoh for a while and said, "You're persistent, as usual."

Later that night, when Kaidoh finally went home, Inui worked on his computer. He heard the front door open, so he closed his applications and stepped out of his room. "Tadaima," he heard someone say. "Okaerinasai," Inui said to his mother, who just came home. His mother smiled and gave Inui a hug. "Tanjoubi omedetou, Sadaharu."

Sadaharu Inui was more accustomed to receive birthday greetings from his parents. But since there was this persistent kouhai who put up with his sadistic glee, it felt like a special year for him for the first time. He smiled and replied, "Arigatou, okasan."

Arigatou, Kaidoh...