Author Notes: Man is this gonna be fun. OOO is one of my favorite Riders, and a badass Naruto wearing the belt, equals win!

Challenge by Nick Terakidan

Genres: Action, Adventure, Crossover

Warnings: Strong Language, Violence, Sexual Content

Tags: Strong/Powerful/Smart/Badass Naruto, Harem, Lemons, Sasuke Bashing, Sakura Bashing, Kakashi Bashing, Kiba Bashing, Council Bashing and Idiocy

Harem: Kyuu (FemKyuubi), Yugao, Mezool, Anko, Haku (FemHaku), Hinata, Ino, Kin, Yugito, Ni (FemNibi), Tayuya

Disclaimer: Naruto is owned by Masashi Kishimoto and Kamen Rider Series is owned by Shotaro Ishinomori. I own nothing but my original characters.

Cue Anything Goes, for it's time for OOO!

Multi Birth King OOO Naruto

Chapter 1 - Re:Birth of OOO

Life sucks, especially if you're a 13-year-old, blonde-haired, blue-eyed kid with whisker marks on his cheeks. He is Naruto Uzumaki, Jichuuriki of the Kyuubi and ninja of a village called Konoha.

Hell began for Naruto when he was born. The Yondaime Hokage, Minato Namikaze, sealed an attacking Bijuu known as Kyuubi inside of Naruto to save the village. The Yondaime wanted Naruto to be seen as a hero, but it wasn't to be, as almost the entire population in the village saw him as the fox reborn. Sure he had his older triplet sisters Naruko, Narumi, and Naruhi watching over him, but that didn't stop the villagers from beating on the poor boy. It was even worse on his birthday, especially since some of his ANBU protectors either ignore their duties or join in on the beatings. Fortunately there were a few kindred spirits who could tell the difference between a sealed kunai and a scroll like Yugao Uzuki, who was appointed personal protector of Naruto by the Sandaime Hokage.

Year later Naruto joined the ninja academy at the age of 7. Although he was talented, his growth was stunted by the teachers, and one of them messed with his chakra during the Genin Exams. He then managed to passed when the Sandaime caught on to what the teachers were doing. Iurka Umino then managed to pass Naruto on his third try when he learned the Shadow Clone Jutsu and was assigned to Team 7 with Sakura Haruno, Sasuke Uchiha, and Kakashi Hatake.

Unfortunately, his own team hated his guts. Sasuke didn't like him since he was the dead-last and Sakura always hit him for the smallest of things. They mocked him for no reason and refuse to help out on D-rank missions. Even Kakashi hates Naruto, thinking that he was the fox reborn and blames him for the death of his sensei. He also plays favorites with the Uchiha, not teaching the others nothing.

On a sidenote, he was suppose to be on Team 8, but the advisors and the civilian council managed to block that move, the douchebags.

Yep, Naruto's life was hell, with his sisters and his surrogate family being the only slices of heaven for him, but things are about to look up.

Wave Country

A lot of things can go wrong when a client hides crucial information. Either someone can get seriously hurt, or a A-rank missing-nin can appear out of nowhere.

This is such a case, one that Kakashi was actually hoping for.

"DUCK!"

A giant sword came out of nowhere, prompting a group of ninja with their client to hit the ground. The said sword passed over them and embedded itself on a tree behind them.

"That was way too close." thought Naruto, hoping that the training that his sisters put him through was about to pay off. Why oh why did he have to wear his orange 'kill-me-now' tracksuit for his mission.

"Oh my god! What was that?" shrieked Sakura, who freaked out.

"What a weapon. If I can get that I can use it to kill Itachi!" thought Sasuke, who was drooling at the possibility.

Kakashi scowled at their attacker who landed on his zanbato-like sword, "Zabuza Momochi. The Demon of the Mist and formerly one of the Seven Swordsman of the Mist."

Zabuza chuckled, "Well well. I never expected to meet you Kakashi Hatake of the Sharingan. Your reputation proceeds you. To think that you would be the one guarding my target and with a Genin team to boot."

"Sakura, Naruto, protect the bridge builder!" Kakashi ordered as he uncovered his Sharingan eye, "Sasuke, assist me!"

Sasuke looked like Christmas has come early as he went to Kakashi's side. Naruto just rolled his eyes as he and the banshee stayed close to Tazuna.

"Well then," Zabuza pulled his sword out of the tree and landed on the ground, "Let's not waste time. Kirigakure no Jutsu (Hiding in the Mist Technique)!"

The visibility is greatly reduced as a chakra enhanced fog rolled in, clouding everyone's vision as hell reigned. After a few tries, Kakashi managed to dispel the mist with a wind jutsu, finding Zabuza within the Genin's formation. As Sakura jumped back in fear, Naruto acted quickly as he grabbed Tazuna and avoided Zabuza's sword swing.

"Not bad kid." Zabuza smirked, "Unlike pinkie, you took a gamble with your life and protected your quarry."

Zabuza then raised his sword to block Kakashi's attack as he made a few one hand seal to summon several water clones to engage the Genin.

Sasuke smirked, seeing this chance to finally show off this power as he engaged the water clone with his fangirl cheering him on, leaving Naruto to protect Tazuna by himself.

"Be honored to fight an Uchiha and rejoice!" he shouted as he clashed with the clones.

"It's a lonely world." Naruto thought, shaking his head.

But when Sasuke started to get the crap kicked out of him after taking out a few of them, Naruto sprung into action, summoning a bunch of Shadow Clones to cover Tazuna and leapt into the fray. But he didn't get far when Sakura decided to punch Naruto, flooring him.

"Ow! What the hell was that for?" shouted Naruto as he tried to get up, but found it difficult due to Sakura slamming her foot on him.

"Stay out of Sasuke-kun's way Naruto-baka!" she screeched, digging her heel into Naruto's back as he held his head in pain.

"What the hell is she doing?" Tazuna thought furiously, "Her own teammate! He was only trying to help."

"What the bloody hell?" Naruto thought angrily, "Kyuu-chan was right about her all along. What was I thinking, crushing on this banshee?"

"Told you so~" said a voice in Naruto's head.

Soon, the water clones exploded in Sasuke's face, sending him into a tree as Zabuza managed to capture Kakashi in a water prison.

"Sasuke-kun!" Sakura cried as she ran to his side, checking to see if he's okay.

Naruto then took this chance to run past his two teammates and took out two Fuma shurikens, throwing them past Zabuza's remaining water clone and to the real Zabuza who was maintaining the water prison. He had no choice but to let go due to one of the shuriken spinning on a direct path for this arms. Zabuza pulled back, freeing Kakashi as he began his counterattack, copying Zabuza's upcoming jutsu as the remaining water clone dispelled.

"Looks like the demon has his uses after all." Kakashi thought as he fired off his own Water Dragon Jutsu at Zabuza.

Just then, Naruto frowned as he felt his clones dispel. As he received their memories, he was trying to phantom why the hell Sakura would attack them. Unfortunately he didn't have time to wonder, as Zabuza and Kakashi fired off their Water Vortex Jutsus. Naruto managed to jump away from the developing tidal wave in time and on top of a tree while Sasuke and Sakura were washed away.

"Oh crap!" Naruto shouted as he produced some rope.

He was about to jump over to save them, but a glint caught his eye. He turned to find a figure far off in the trees wearing a mask and senbon in hand. For now the figure wasn't moving Naruto noticed, so he threw the rope around Sasuke and Sakura. It whipped around them, allowing Naruto to reel them in. As he pulled them up, something unexpected happened, as he suddenly found himself in front of Zabuza as the latter was swinging his sword.

"What?" thought Naruto, confused as Zabuza widened his eyes.

"Oh no, I can't stop. That bastard!" Zabuza roared in his mind.

Time slowed down in that moment. The large blade sliced through Naruto's chest, sending his 4'9 frame flying over the forest.

Zabuza was enraged as he rounded on Kakashi. That bastard used the substitution jutsu on his own ally. Zabuza may be a 'demon', but what Kakashi did was way over the line.

"You can rest in peace now sensei." the scarecrow thought as he turned back to his opponent, "What the?"

Caught off guard, Kakashi had to reengage Zabuza, who was now attacking him in a berserker rage state.

Later in an Unknown Location…

Naruto woke up and shook the cobwebs out of his head. He then looked around to find himself inside a dark tomb.

"Where am I?" he wondered as he checked himself. He smiled when he found that his wound was healed.

"Thank you Kyuu-chan." he thought.

"Anytime Naru-kun." she said, returning the smile mentally.

Yes, Naruto knows about the Kyuubi no Kitsune, However, he is really a she, and her name is Kyuu Kurama. She did not attack Konoha by choice. It was thanks to a masked guy named Madara Uchiha. More on that later.

As he got up, Naruto eyes fell on a large coffin that was in the middle of the room. He walked over to it and gasped along with Kyuu at what they saw.

"Naruto…" Kyuu began, excited "You just hit the fuckin' JACKPOT!"

Inside the coffin were two belts with strange device on them. One had a rectangle buckle with three slots on it and a circular device on the side with a coin holder on the other side while the other belt was gray with a green orb and a coin slot. In addition there is a thin case which Naruto picked up and examined.

"Just be careful Naru-kun. I fear that once you open that case, there will be no going back." Kyuu warned him.

Naruto nodded, "It'll be all right." he assured her was he opened the case.

A weird sensation flowed through Naruto as energy wrapped around him in a display like a lightshow. As pain started to surge within him, images that appear to be memories flowed through him. Memories on how to use the belts, revealing them to be suits of armor. Memories of the ones who used to use the two armors. They used them to fight monsters known as Greeed. As this was happening, multiple colored coins shot out of the case and circled around Naruto. There were red, yellow, green, gray, blue, black, orange, pink, silver, white, and gold coins, and they all went inside Naruto. One of the red coins however, gathered some silver medals before becoming a red arm with a bird motif that attached itself to Naruto's right arm.

"Amazing…" Kyuu said as she viewed the incoming memories, "Not only do the memories shows the life of the users of these belts, they're like instruction manuals. And the belts, they're bonding to you while the coins are adapting to you."

Naruto heard but wasn't able to respond, as the power filled him completely, making him roar with satisfaction, shaking the tomb he is in.

"Look out world, and Kono-stinksville." Kyuu sneered as she felt Naruto's new power rise, "Naruto Uzumaki's been reborn as a Kamen Rider, and this time, no more Mister Nice Guy!"

What that, a bright light consumed the tomb.

Unknown Location...

A man in a red business suit was humming a tune as he put the finishing touches on a cake he made in his office.

"Happy Birthday to you. Happy Birthday to you. Happy Birthday dear…"

He then wrote a name on the cake, with it reading…

'Multi Birth King OOO'

He then put on a smile.

"Welcome back OOO. Welcome back Birth. And HAPPY BIRTHDAY!"

END OF CHAPTER 1

Next time on Multi Birth King OOO Naruto

-Naruto and Kyuu meets the Greeed.

-Kyuu makes Naruto fetch a new wardrobe.

-While training, Naruto meets a young girl.

The story is only just beginning, so stay with us for... more new tenants... more insane training... and more, Multi Birth King OOO Naruto!

Release: Thursday, April 12, 2012

Edit (4/12/2012): Corrected a few errors.