Disclaimer: I do not own Kamen Rider or To Love-Ru.

Happy Birthday to you.

Happy Birthday to you.

Happy Birthday! Happy Birthday!

Happy Birthday to you!

Happy Birthday to you!

Happy Birthday to you!

Happy Birthday dear…

...

Happy Birthday to you!

The High School King
Chapter One
Happy Birthday!

(First Person)

Do you ever get that weird feeling? Like you really, really should not have gotten out of bed this morning?

It's probably a feeling like what I'm feeling right now, as I glare at the mantis-like monster across from me. I'm wearing some kind of multi-colored armor that you'd see in a tokusatsu show, only this isn't some set and I'm not going to be paid for this later.

Probably.

No, this is real life. This is a real life-or-death situation here.

You're probably wondering how I got myself in this situation in the first place, aren't you? Well, that takes a bit of explaining.

No, not just a bit, let me correct myself. It takes a lot of explaining.

My name is Sato Takehiko, or Takehiko Sato for you English speakers, but either name works. My morning started out typically enough, wake up, head to school, and meet up with the guys…

Right, I share a house with two other people- Rito and Mikan Yuuki. Rito is the older brother, and Mikan is his younger sister. I go to the same school as Rito, and I've known him since I was about six or so. I guess you could say we're childhood friends. My parents travel a lot, so I rarely see them if at all, and Rito's parents are… well, busy all the time. It was decided between our parents that we would live in a house together so we could go to the same school.

So today I found Rito doing what he usually does: Stalking- er, I mean watching, his crush from afar, Haruna Sairenji.

I've only talked to the girl once in passing, but she seems like a nice person. Far too shy, though. I don't ship it.

I smirked as Saruyama and I snuck up on Rito as he watched her from around a corner. Saruyama is essentially our third musketeer, so I've known him for a while too. One thing to know about our group is that while Rito is extremely shy about girls and Saruyama is practically the opposite, I stand sort of in the middle of that spectrum. I consider myself the "normal" one.

"So, are you gonna do it, or am I?" I asked him. He turned to me with a smirk rivaling my own.

"I've got this, leave it to me." He whispered back, rolling up his right sleeve. He cupped his hand to his mouth and yelled "Yo, Rito! Are you stalking her again in the middle of the day?!"

3… 2… 1…

"WHO'S THE STALKER, BASTARD-?!" There it was, Rito exploded violently. He's got a bit of a temper, but I think that's normal for guys our age.

"You mean you weren't just doing that?" I asked, full deadpan. Rito glared at me, "Come on, we all know you were watching her just now. Like usual, right?"

"Shut up. I wasn't just watching her today. I'm waiting for a good time."

PFFT.

"Ohkay, I know that wasn't supposed to sound sexual but…" Rito gave me a sharp glare, so I relented "Fine, fine. So, you're going to try it again?" I asked.

"Yeah, I've decided." He said looking resolved, "I'm going to confess my love to her today."

Saruyama rolled his eyes, "Right. Like all the other times you tried?" He muttered off-handedly.

Here's the thing. Every time Rito tries to confess to Sairenji, something happens to make him fail. It's happened every time before now, and it'll probably happen again. It's almost like they're not meant to be together, by royal decree of the god-king of the universe.

But here's where it's different this time. Sairenji and Rito are in the same class this year. It's the first time since the eighth grade they've been in the same class. This increases his chances of telling her by like… I dunno, a million or something?

"So, when do you plan on telling her?" I asked.

Rito blinked, "I… actually haven't considered that." He admitted sheepishly, "But I guess this afternoon."

Ding-Dong, Dong-Ding-Ding

The school bells sounded, signifying that it was time to get to class. I sighed.

"Right, let's get to class. Good luck on telling Sairenji, Rito." I said as I turned and started my walk to class.

Classes today were the norm for the first few days of school. Since it was the start of the school year, all the teachers were focused on reiterating the school rules, going over the syllabus, those sorts of things.

Really, all that did was give Rito time to think about how he was going to confess to Sairenji, because he stood resolutely at the gate when it came time to leave school.

I gave him an encouraging pat on the shoulder as a passed, "Give it your best. I'll wait for you around the corner."

He didn't even nod. He was that focused.

I peeked around the corner to watch, as Rito froze when Sairenji walked in his direction. I shook my head, "He's not going to be able to do it." I murmured. Just as I expected, Rito dove into the nearby bushes instead of spilling his heart out to Sairenji.

The girl looked around, confused, "Huh? Is it just me, or did someone call my name?"

She shrugged, and continued walking, right out the gate and past me. Shortly after, Rito walked out the gate.

It doesn't take a second look to tell how dejected he's feeling.

"So you couldn't do it." I murmured, putting a hand on his shoulder as we walked.

"I couldn't do it…" Rito mumbled, before pulling at his own hair. I take a step back as he starts to yell, "Why couldn't I do it?!"

I laughed, "Hey, Rito, no point in looking so mopey. You'll have plenty of opportunities to tell her how you feel." I told him.

He seemed to brighten up at that, "Yeah! You're right. Just because I didn't tell her now, doesn't mean I can't tell her later."

"Yeah, man! That's the spirit. And remember, you have the support of me and Saruyama to- "

Clink

Whatever I was saying at the time was interrupted when a coin fell in front of us. I bent down to pick it up, and looked at it. The coin had a strange design, mostly red with a golden edge. There was a picture of what I guessed was a bird on the face of the coin, and on the other side there was a single horizontal line.

"Huh. Looks like it's our lucky day, huh Rito?" I grinned and looked at him. He apparently didn't share my sentiment, judging by the frown.

"Speak for yourself. Besides, that coin is bigger than any I've seen. I don't think anyone will accept that." He said, immediately shooting me down.

I chuckled briefly, "We'll see about that." I responded, making my way over to a vending machine. Just before I put the coin through the slot, a voice commanded me to stop.

"STOP!"

"Huh?" I looked around. There was no one that could have said that, and it certainly wasn't Rito's voice. I don't think that he could bring his voice to do that. I shrugged, passing it off as my imagination, and went to put the coin through the slot. My fingers slipped, and the coin fell to the ground, and rolled under the vending machine.

Rito and I stared at the bottom of the machine for a few seconds before I spoke up.

"Such misfortune." I muttered. I walked over and grabbed the machine.

"What are you doing?" Rito asked as I lifted the vending machine up so it sat on its back legs.

"Quick, grab the coin. I can only hold this for so long." I said, my arms already shaking from holding it.

"Oh… Okay!" He said, crouching down. He looked under the machine for about five seconds before backing away screaming.

"AAAAHHH!"

"O-Oi! What's wrong?!" I asked, dropping the machine with a dull thud. For a second, I thought I heard someone yelp in pain.

Rito gulped, and pointed at the machine, "T-There's something under there!"

"Huh?" I asked. Rito suddenly became very focused on something over my left shoulder, "Rito… What's behind me?"

He broke out in a nervous sweat, "Y-You might want to see for yourself."

I slowly turned around, only to be face-to…

Hand. FLOATING HAND. It chuckled at me briefly, waving the red coin around.

"Heheh… I'll be taking it back now; my Core Medal." It said. I didn't even register what it had said before I both screamed and threw my leg up, kicking the hand and knocking the coin into the air. All of it, accidental.

The coin fell into my hand. I looked dumbly at Rito.

"A-A floating hand… What do we do?" He asked.

"Hey!" The hand shouted, climbing back from behind the vending machine, "That hurt, you..."

I gulped, and gave Rito the most courageous look I could muster at the moment, "Well, Rito. There's only one thing we can do in this situation. It's a secret art I've developed, but it depends entirely on yourself to execute." I said.

"I have a bad feeling about this." Rito commented.

I grabbed his arm and took off, "RUN FOR YOUR LIFE!" I yelled at the top of my lungs.

"Hey, wait! I said wait!" The hand yelled after us, before flying in pursuit.

"Where are we going?!" Rito asked, pulling his arm away from me. I thought for a moment, before looking ahead.

"There's a courtyard ahead. We'll lose it there." I told him.

But seriously, what's with that hand?!

As if on cue, the hand flew down in front of me, causing me and Rito to stop. Oh right, it can fly.

"Whoa!"

"Give back that medal. It's my body." It announced. I stared at it, unable to speak.

"Your body…?" Rito asked.

The hand flew up to me and grabbed the collar of my shirt, pulling me off the ground.

"W-Whoa! For a single hand, you're pretty strong." I commented, forcing a smile.

"Enough talking. Hand over the medal, now! I'll let you live until then." The hand said.

"Y-You're going to kill me?! H-Hold on for a second, I found this coin on the street, and…" I explained, holding up my hands in a placating manner.

"Yes. You "found" it because I dropped it." The hand said, gesturing for me to give the coin back.

"O-Oh, did you? What a coincidence, for you to be there while Rito and I…" I muttered.

Rito noticed something, "Hey, guys." He said, but we ignored him.

"Just give it back." The hand growled.

"Uh, hey guys!" Rito shouted, drawing our attention.

Both the hand and I looked at him, "What do you want?" We asked at the same time. Man, he looks freaked out.

"There's, uh, something coming!" He said, pointing off to the side.

"That Core Medal… Hand it over." A Monster said. It was huge, and a shade of light green. If I were to compare it to an insect, I'd say it was a mantis. It had no eyes, and in it had two large blades inside its hands. It also had an extra set of arms closer to the chest.

"Oh man, another one?!" I exclaimed. The monster brought its scythe-like arms together and created four blades of energy, "Oh shit…" I muttered as it threw the waves of energy at me.

"!"

The hand rushed forward and blocked the energy attacks, destroying them with swipes of his… hand.

Huh. The hand that threatened to kill me just now saved my life. I don't know whether to be thankful or terrified. I'll settle for the former.

The monster grunted, surprised.

"You're… Ankh?!" It exclaimed.

"Don't interfere. That's my Core Medal." Ankh said, gesturing angrily.

Rito walked a little closer to me, "What's going on?" He asked.

I gave him a serious look, "I don't know… This looks like something you'd see in a Sentai show." I muttered.

"Hand it over…" The monster said, before charging toward Ankh, swiping madly. Ankh dodged the first swipe, but got hit by the rest.

"Gah!" The hand yelled as he was sent rolling across the pavement.

The mantis monster picked him up, and if it could glare, it would have, "Stay out of my way!" It yelled as it threw him into a nearby board.

"What do we do?" Rito muttered.

"Well, we have to do something." I said, "This fight is a little too one-sided. Come on. Let's help Ankh."

Ignoring Rito when he asked me if I were crazy, I ran toward the mantis monster, grabbing its arms before it could do anything else. It easily threw me off, and I landed on a table that couldn't support my weight, causing it to crumble as I hit it.

"Gh!" I grunted. I watched as the monster closed in on me, bringing its scythe-like hands together and creating a shink noise as it did. Just as it was about to reach me, Rito jumped on it.

"Get away from him!" He yelled, not letting go of it as it struggled.

"H-Hey Rito, be careful!" I shouted at him, just as the monster struggled out of his grasp. The monster sent a quick kick to Rito's stomach, sending him rolling away. The monster brought its arms together, and sent an energy wave at Rito.

"RITO!"

It hit. Rito's right hand stopped being a part of his body, hell, it stopped being a thing in general. What was left dropped to the ground, just a mesh of tissue and bone. Rito clutched what was only a stump and fell to his knees, screaming.

"No... NO, RITO!" I yelled, as the monster slowly walked toward him, "STOP!" I yelled, standing up and running at it. As if on instinct, the monster turned and grabbed me. I was thrown to the side like a ragdoll.

"Ow…" I mumbled as I nursed my head. The monster quickly closed in on me, and grabbed me by the shirt.

"He's a total idiot, but… I can use him. It's not like I have any other choice." Ankh said, taking flight. The monster noticed him flying toward us, and jumped away, with me still in its clutches. My body hit a pole, and I was dropped.

Before I hit the ground, Ankh caught me.

"You. What's your name?" He asked.

I looked up at the floating hand, "It's… It's Sato Takehiko. But call me Sato." I said.

"Sato. You've impressed me. I'll show you how to survive this." He continued, before a pink glow emitted from him. A shape came from the bottom of his wrist, and solidified into a stone object.

"Hey, can you save Rito, too?" I asked.

"Worry about that later. For now, we must deal with him." Ankh said, pushing the object to my waist. The object glowed for a second, before turning into a belt that wrapped around my waist.

"W-Whoa!" I yelped, startled by the sudden change.

Ankh turned to look up at the Mantis Monster, "The Core Medals aren't the only things I took, as you can see." He said, and turned to me, "Sato. The only way out of this is to defeat him."

"I know, but how?"

"Slide these three core medals in here." The hand said, holding two more of those medals; a yellow one and a green one. He then pointed to my belt, "It'll give you the power to do it." He held the medals up to me.

I took them, and examined them for a brief second before looking back at Rito. He was bleeding a lot, but had stopped screaming and looked barely conscious. The Mantis Monster was making its way toward us.

"Listen to me, boy. Don't do it, don't let Ankh tempt you. There'll be consequences if you use that thing." It growled.

Ankh bumped my chest, getting my attention, "Hey! What's a little risk? You want to save your friend, don't you? Then you need to save yourself, first." He said.

"Do it, Sato! Transform!"

"Don't!"

I looked at the monster, then back at Ankh. I allowed myself to smirk, "I don't think there's any other way for me to get out of this easily, so… Looks like we're in the same hole." I said, flicking the red coin in the air. I caught it, and slid the red and green medals in, then the yellow. I pushed the belt buckle so it was diagonal, which caused a pulsing sound to emit from the belt. Ankh grabbed a small, circular device from the side of the belt.

"Now use this." He said, letting me grab it. The belt made a clinking sound as I brought the device across the belt buckle.

"Henshin!"

TAKA, TORA, BATTA! Ta-To-Ba! Tatoba, Ta-To-Ba!

The belt sang as several colored circles flew around me, eventually stopping at a Red, Yellow, and Green combination. They flew into me, and the unthinkable happened.

Multi-colored armor formed around me, themed after those colors.

I gave myself a once-over, "Cool…" I breathed, "But hey Ankh, what was that song just now? Hawk, Tiger, Grasshopper? What is this armor?"

"That idiot!" The monster yelled.

"Yes, just as I'd hoped." Ankh muttered offhandedly, before flying over to me, "Don't worry about the song. This is Os. You'll understand how powerful it is once you fight."

Before I could say anything in response, the monster jumped at me, brandishing its arms. I blocked, and kicked it away. The monster rolled on the ground as… coins? Spilled from it.

And that's how I got into this situation. The mantis monster glared back at me, before charging at me again. I blocked it with the blades on my wrist, and struggled against the monster's blades.

I pushed some power into my arms, I don't know how, and the blades on my wrists flipped into claws.

Tiger. I understand now. I used the claws to slash across the monster's chest, more of those silver coins spilling out, "HA!"

"So, if I push power into my arms and claws come out, then if I push power into my legs…" I thought aloud. If this works, it's gonna be so cool…

The armor on my legs glowed, and I crouched. In a burst of power, I jumped toward the monster, who was recovering from my slash. I kicked it several times, landed, and sent a powerful punch into its chest, "Ha!"

I laughed as the monster landed on its back, "This is so cool! Hahahaha!"

"You..." The monster growled, as it glared up at me. It jumped to its feet, and charged at me again, brandishing its scythes.

Uh-oh.

I hadn't expected it to recover that fast, and took the full force of the slashes, "Gh!" I grunted, and the yellow parts of my armor emitted a static-y sound as it flickered.

"Huh…?" I muttered.

"Hey!" Ankh yelled, getting my attention, "Swap out the middle one with this!" He said, as he flipped a lime green coin to me. I caught it, and kicked the monster away before it could attack me.

Swap it out…?

I took the yellow coin out, stored it, and put the lime green one in. I brought the disc across the belt.

TAKA, KAMAKI, BATTA

Once again, the circles formed around me, and changed my armor. My arms changed into a lime-green color, with scythe-like blades on my wrists.

"Alright!" Ankh exclaimed, giving me a thumbs-up.

The monster got its self back into a fighting position, "Ankh! Hand over the medals, now!" It yelled as it ran at me. I dodged its blades and hit it with my own, sending it rolling across the ground.

I charged power into my arms, and leapt toward it, my scythes glowing. I hit the monster, and it was sent flying.

Ka-BOOM

It exploded, "Why did it explode?" I asked aloud, as the coins fell to the ground. I feel like I'm forgetting something- Oh.

"RITO!" I yelled, running over to my friend. He was quiet; there was a pool of blood under him. He's just barely conscious.

"Sa…to?" He whispered, before coughing.

"H-Hey Rito, hang in there! I'll call an ambulance." I said, reaching for my phone, only to realize I was still in my armor.

"Do you want to save your friend?" Ankh asked, floating around Rito. He looked at me, or whatever counts as looking at me considering he was a floating hand.

"What? Of course I do!" I exclaimed. What kind of friend- No, what kind of brother would I be if I didn't?

"Heheh…" Ankh chuckled as he floated toward Rito, "Very well. I can save him, but it requires me to become his right hand. Normally, I wouldn't consider this, but this would be beneficial to the both of us."

I thought of what he said for a few moments, before nodding, "If it will save him, then do it."

Ankh made a fist, and moved to where Rito's arm would be. He pulled Rito up into a standing position, and my friend stopped bleeding. The wound had sealed!

His entire body flashed purple, and his hair became a dull blonde, changing into a completely different style than what I was used to seeing on Rito.

I stared for a moment, before trying to speak, "Ankh?" I tried.

He gave me a smirk, "The boy was unconscious, so I have to take control of his body while it heals." He spoke through Rito's mouth. One thought crossed my mind, and I immediately grimaced.

This is going to be a god-damn nightmare to explain to Mikan.

Happy Birthday to you.

Happy Birthday to you.

Happy Birthday! Happy Birthday!

Happy Birthday to you!

Happy Birthday to you!

Happy Birthday to you!

Happy Birthday dear…

OOO

Happy Birthday to you!

A/N:

Well hello everyone!

Welcome to a project I've wanted to do for a while now. I'm rewatching Kamen Rider OOO and re-reading To Love-Ru just to do this. I'm also looking for ways to deviate from canon in both series as I go, so this should be fun! I have a lot of ideas, some of which you, the readers, have already seen in this chapter!

Anyway, let's get onto the details.

Sato Takehiko: I originally wanted the main character to be Rito, but he just… didn't fit with me, him being Os. So, I decided to create Sato. In a way, he's like another sibling to the Yuuki twins, having known them from a young age.He's also the Kamen Rider OOO of this universe, but not the only Kamen Rider. Other Riders, like W or Fourze, may make appearances, or may be mentioned later.

My decision to make this first-person might make this a little difficult to write in some cases, but I'll do my best!

Though his name is Takehiko, he has everyone call him by his surname since it's easier to say.

Ankh possessing Rito: I thought this would be a good twist, one that involves both series. So yeah, Ankh is going to be acting as Rito's right arm. Not much else to say here, other than how Rito's luck is going to affect Ankh. Oh, and Mikan. Dear God, Mikan.

And that's all I have to say. I might change the viewpoint if it becomes annoying to write, because I can't write scenes that Sato isn't directly involved in.

Please review! It's good for my motivation to continue writing this story. Like it? Hate it? Have a suggestion? I'll read your post and reply.

Have a great day, children! This is Zappy Caboose, signing off!

(This chapter has passed under the eyes of my wonderful unofficial beta-reader, XDNOVA13. That said, if you happen to notice any mistakes, please let me know. Thank you for reading!)