Hello FanFiction! This is pain17ification posting a new Xover story called "Heart of a Ninja"!

Please note: pain17ification doesn't own Naruto or Kingdom Hearts



"Kurama Talking/Techniques"

(Translations and A.N. Numbers)

[Scene Shift]

Chapter 1: Meeting in the Darkness

The sound of waves hitting the shore was the first thing he heard as he woke up. His body was wracked with pain and it hurt to even twitch or breathe. What happened and where was he? Why was he hearing the sound of water when he was nowhere near it?

He slowly opened up his eyes, revealing bright blue irises to the world, and painfully sat up. The first thing he saw was the dark sand of the shore. It wasn't a natural tan or even a rare white, it was a dark gray. He turned his gaze and saw the sea, but the water was as black as night and the only source of light in the area was a silvery moon on the horizon. He kept moving his gaze and saw that he was next to a rock face and that thorn like structures stretched over the water, but they didn't go that far.

What was this place? Why didn't he feel anything from it? All he felt was emptiness and pain, though the latter was because of his still healing injuries. He made to rub his head, but he stopped when he felt something move within his grasp. He looked down to his right hand and gaped at what he was holding.

It was…a weapon? He didn't know, but it sure looked like one. The handle was a dark red, almost like blood, and had a guard that surrounded his hand. The guard was a bright orange and had a silver chain on the bottom of it that had a keychain at the end. The keychain was in the design of a red swirl with a black outline on it. From the top of the handle, a black blade stretched for about three feet and a black fox head protruded from the side at the top of the blade. The fox head's eyes had red sclera, a bright orange iris, and a black slit pupil.

A voice whispered in his head and echoed, "KeyBlade…"

His brow rose slightly in confusion. Key…Blade? What was a KeyBlade? And why did he apparently have one? He closed his eyes and tried to speak to his friend, but they widened in shock when he couldn't hear anything. The voice he had grown accustomed to hearing from within his mind was gone and where his friend once resided in his mind was empty.

What was going on here? First he wakes up on a dark shore, then he apparently has a weapon known as the KeyBlade, and now he can't hear or talk to his last known friend.

He then closed his eyes in thought and tried to remember what happened before he woke up here. The last thing he remembered…


He was panting and nearly out of energy as he stood before the last two Uchiha; Obito and Sasuke. His clothes were torn, his headband destroyed, and his skin riddled in cuts and bruises. Of course, the two Uchiha weren't much better and Obito had his Sharingan cut into, making it useless; so that was a plus.

Kurama, the Kyuubi no Kitsune and his last surviving friend, had given him all of the energy he could take and it was barely enough to take down the Gedō Mazō (Demonic Outer Statue) and the chakra it had stored within it. Now, he barely had half of his reserves left and Kurama was focusing on regaining his own lost power.

"It's over for you, Naruto," Obito said calmly. "You may have stopped the Gedō Mazō, but I will still rid this world of its light!"

"This is the end for you, dobe," Sasuke stated as his Susano'o (Tempestuous God of Valor) surrounded him with its dark and corrupted power.

Uzumaki Naruto lowered his head as tears welled from his eyes. The war…the Fourth Great War had taken its toll on everyone and left him with no one but the fox sealed within him. His friends, his precious people, were all gone or close to gone. He couldn't save them, even if he desperately wished to. 'How did it come to this, Kurama?'

"I don't know, Naruto… Perhaps…Darkness is the real source of power in the world…"

Naruto clenched his fists in anger as he rose to his feet. His head was still down, with the bangs of his golden blonde hair shadowing his blue eyes. 'No… Darkness can't be the real source of power. It may seem that way since this world is being plunged into it, but even in the deepest Darkness…Light shines on through!'

With that though, power exploded from him; power he didn't have before. Where before his chakra was a bright blue, it was now nearly white and shone brightly throughout the battle field with its glow.

'This power… Where is it coming from? It feels so warm…so bright,' Obito thought in confusion as he readied his war fan and Sasuke readied an arrow with his Susano'o.

'Kurama…do you feel it?' Naruto asked his tenant suddenly.

"Yea, I do… It feels like Darkness is engulfing this world and this power you've tapped into is holding it back; but it doesn't look like it will last forever…"

'Yea… I figured as much. But it looks like its pooling around the two of them,' he commented while referring to the Uchiha.

The Bijuu hummed in thought as it looked through Naruto's eyes and saw dark puddles form near the two Uchiha. From the Darkness, two glowing yellow orbs appeared in each and began to rise from the puddles. The Darkness took shape and form and stood behind the two Uchiha with its head tilted in wonder.

It had a round, spherical head with circular, glowing yellow eyes. It also had two long, twisted antennae sprouting out of the top of its head. Each of its hands had three clawed fingers, and its feet were large and lacked any discernible digits. With the exception of its eyes, the body was completely black and blended in with the shadows easily.

Before the Uchiha knew it, the creatures began to latch onto them and were unaffected by the retaliatory strikes that were launched. Even the Susano'o proved ineffective as the creature simply phased through it and latched on to Sasuke. The Darkness from the creatures engulfed them and surrounded the Uchiha in twin spheres of pure dark energy. Their cries of pain soon faded and when the spheres disappeared and presented them, Naruto was left shocked at what he saw.

Obito had become a large lion made of Darkness with glowing yellow eyes and sharp yellow fangs. As for Sasuke, he became a large winged creature that had a hawk's body, but the neck and head were that of a serpent. Like Obito, his body was pure lack, save for the eyes and fangs which were a bright yellow.

The two new creatures of Darkness turned to Naruto and bared their fangs at him, making the blonde tense and prepare to defend himself. However, it wasn't needed as dark puddles appeared beneath them and they sank into them, leaving without a trace.

As soon as they were gone, the land surrounding Naruto became engulfed in what could only be described by him as an enormous dark puddle with him standing in the only unaffected area. However, the area was slowly getting engulfed as well and he began to panic. 'Kurama, what do we do?!'

The fox growled as it wracked its brain for any ideas. Soon, one came to it and it began to mold its energy in a way it never did before. The blonde felt the fox's power form in his right hand and looked to see a swirling mass of red and white energies. "Quick, before I lose focus, slam your hand on the ground and unleash the energy! We're leaving this world!"

'What do you mean?! Why are we leaving when we could try and save others?!'

"Kid, trust me… They're already gone… You're all that's left. Now slam your hand and let's get out of here!"

Naruto cursed as a tear left his eyes. He then slammed his energy-filled hand on the ground beneath him and unleashed the power within it. He was then surrounded by the energy and felt his body fade away. Before he fully disappeared, he whispered out, "I'm sorry…"

[End Flashback]

'I remember now… My world was engulfed in Darkness and I had to leave… But then, what happened to Kurama?' he thought while he looked to the KeyBlade in his hand. 'Did he become this…weapon? If so, why a KeyBlade and what exactly can this thing do?'

He was interrupted from his thoughts by a soft gasp and he turned to see a beautiful young woman standing about fifteen feet from him.

She had bright blue eyes like his and short, blue hair that reached her shoulders and framed her heart shaped face. She wore a black and blue, high-collared halter top with two pink, intersecting belts over her chest, and black shorts. She also had an odd silver badge similar to badges that looked to be a Heart above a Cross. On her arms were white bell-sleeves and tan, fingerless gloves. She also wore a small, segmented piece of armor on each of her upper arms and what appeared to be black stockings, or socks, on her legs which reached halfway up her thighs, leaving a small area of bare skin on her upper thighs. Her attire also bore two strips of blue cloth that draped over either side of her hips, along with a smaller, white strip of cloth tied around her waist and draped in the same manner. Finally, she had pointed, armored, silver boots with a sharp hook-like extension on the outer side of each.

He kept looking at her while she had her gaze on his weapon. 'A KeyBlade! But I thought that Ventus, Terra, and I were the only ones? He doesn't look like Sora or Riku either since Terra and I instilled some of our power into them… Who is he?'

Naruto slowly and painfully rose to his feet, using his KeyBlade as a crutch to support him. "Hey, my name is Uzumaki Naruto," he greeted in hopes of having not stumbled upon an enemy in his weakened state. "May I ask yours?"

The woman was shaken out of her thoughts at his voice and she gave a small, friendly smile. "My name is Aqua, and I'm glad to have run into another Key Bearer in this place."

"Key Bearer? What do you mean?"

Her eyes widened in shock at his confusion. "You mean that you don't know what you're carrying?" she asked while pointing to his weapon.

He raised it up and looked to it in confusion. "You mean this thing? I heard a voice in my head call it a 'KeyBlade' but I still don't really know what the heck it is."

"A KeyBlade is a weapon used to fight off either the Darkness or the Light. Most are used to fight the Darkness, but there are still a few that go against the Light. Do you know what yours fights against?"

Once again, his face had a look of confusion before a voice whispered in his head again. It echoed, "Rise up with the Light… Fight the Darkness…"

"It fights against the Darkness… At least, that's what that voice told me just now…" he answered her unsurely.

To his relief, she smiled brightly at him. "That's good to hear. I'm actually glad that I found someone else in here. I was beginning to think I was stuck here alone…"

"Where is here anyway?"

"This place," she began while waving her arm to their surroundings, "is known as the Realm of Darkness… I came here after I saved my friend from getting stuck here. I took his place and got stuck here in the process. What about you?"

"I…I don't really know… I mean, the last thing I remember was fighting in this war and seeing the Darkness slowly engulf my world. My friend gave me his power and mixed it with mine before I used it to leave my world. Next thing I know, I'm waking up on this beach with this KeyBlade in my hands."

"You were in a war?" she asked him in shock. "You don't look like you're even 20yrs old! Why were you fighting at such a young age?"

"I was fighting for peace," he said with narrowed eyes as he gazed out to the sea. His tone froze Aqua in place and she listened to him explain. "In my world, we're taught how to fight at young ages and how to protect our homes and precious people. I may be only 17 right now, but I still know things that most adults from my world don't even know. I know what it's like to fight for what is right…and how to lose those you love…"

Aqua's eyes turned sad at the bitter tone in his voice when he spoke of loss. It still amazed her that someone three years her junior could fight in a war, but then again Ventus was only 14 when he fought with her and Terra at the KeyBlade Graveyard against Xehanort and Vanitas. Hearing about a 17yr old fighting for those he cherishes and for peace wasn't that farfetched.

"I'm sorry to hear that… I never thought you'd have to go through all of that."

Naruto turned to her and saw the regret in her eyes at her question. He placed a reassuring hand on her shoulder and met her regretful eyes with his own slightly happy ones. "It's alright… I'd have to talk about it eventually and you didn't know. You don't have to apologize, Aqua."

Aqua met his small smile with her own and gave a small nod. "Alright, and if you need to, you could always talk to me about it."

"I appreciate that, Aqua."

She then looked to the unmoving moon on the horizon and sighed sadly. "It looks like we're going to be here a while."

Naruto sighed as well before the two sat on the shore; Naruto groaning slightly as his pain-filled body protested against the movement.

Aqua looked to him in concern and questioned, "Are you going to be okay?"

He clenched his eyes in pain as he finally sat on the ground. "Yea, I'll be fine after some rest. I just have some wounds from my last battle."

"If you're hurt, I can heal you," she offered as she summoned her KeyBlade, Stormfall, in a flash of light.

The guard was circular and somewhat jagged around its edges while the upper half of the guard was black, the center was grey, and the bottom of it was white. The handle was a featureless, grey rod and the shaft of the KeyBlade was thin and navy blue in coloration; except for the tip, which was silver. The base of the shaft also sported two diamond-shaped bumps and the teeth were comprised by a rectangular frame lined with four short, blunt spikes. This frame and the spikes were all navy blue. The teeth also had three silver pieces bent at right angles; two on the inside corners of the frame and one on the inside center of one side. The Keychain links and token resembled water drops in the rain.

"Just hold still and I'll fix you up," she said as she pointed the tip of her KeyBlade at him. "Cure!" she cried as a small flash of green light shot from her Key and hit Naruto. The blonde immediately felt his wounds close up and heal at a rapid rate. Five seconds later and his body was back at 100%.

He carefully moved various parts of his body and checked for any twinges of pain or any aches. It surprised him that there were none and he was perfectly healthy. "That's amazing… I feel better than ever!" he exclaimed with a smile. His smile turned into his famous fox-like grin as he turned to Aqua. "Thanks for that, Aqua-chan!"

Aqua smiled back at him before what he said rang through her ears. "What does 'chan' mean?"

"Oh, in my world, 'chan' is an honorific used for friends in terms of women. For men, the honorific is 'kun'."

"Y-You see me as a friend? But we just met," she asked in confusion.

"Hey, anyone who would selflessly heal me and speak to me as nice as you have is a friend in my book!" Naruto replied with his grin in place.

Aqua looked to him in slight surprise at how accepting he was before she smiled back. This young man in front of her was different… Not in a bad way, but still not exactly in a way she was used to. Most people she met weren't nearly as accepting as him, but he had this aura about him that just made you want to befriend him.

Her smile still in place, she reached her hand out to him and held it before him. When he looked to it and then her in confusion, she elaborated, "Well then, here's to a new friendship, Naruto."

His grin returned when he grabbed her hand and shook it.

That was the start of their friendship in the Realm of Darkness and they were happy to have someone to be beside in the lonely place. After some time, Naruto asked the KeyBlade Master to teach him how to better wield his own since he had zero experience with weapons other than kunai and shuriken. Since she had never taught anyone before, due to being a new Master, she was obviously nervous about teaching him. However, when she saw the drive in his eyes, she couldn't turn him down.

She started him off with basic stances and forms, to allow him to get a better feel with his weapon. After some time, she then had him move on to more advanced forms, but she found out that her style of "Flowing Combat" wasn't really suited for him. While she "flowed" around the battlefield, he shot through it like a bullet and used deceptive strikes to deal damage. So, she had him work with that and develop a "Trickster" style of combat that made him disorient the enemy with his speed before going in for unexpected strikes. He took to that kind of fighting like a fish to water.

The next thing she had him try was Magic. When she explained how Magic was drawing the power from your KeyBlade and using it in various ways, he told her about how his chakra worked in a similar manner. When he demonstrated with his Kage Bunshin (Shadow Clone), she was left speechless at the display. It turned out that teaching him how to summon forth Magical Power was much easier since he was already used to drawing forth and utilizing energy. He even had a specialized element like she had. Where she had favored Ice and Healing Magic, he surprisingly favored Wind and Light Magic. His Light magic mainly came in the same form as Reflect magic, but it was also able to be utilized as a ranged attack. She was amazed at how prodigious he was with her teachings.

The final thing she taught him didn't use the KeyBlade. It was actually using the power of his KeyBlade to form a specialized Armor like she had. When he asked her about it, she pointed to the pieces she had on her and told him of how, when activated, it would cover his entire body for better protection against the Darkness and even let him survive the Doorways between other worlds.

When he asked her to show him hers, she complied and summoned forth her Armor. Her Armor was mostly colored in shades of silver, black, grey, and blue. Notable additions that Naruto saw included a silver breastplate resembling an upside-down crescent moon and a dark-visored helmet. Her helmet bore two prongs on either side, with her silver ones wrapping around the sides and angling diagonally downwards. She also wore a cape that was a dusty-rose color.

It amazed Naruto that she was able to summon forth something like that, but it confused him as to why she didn't use it to escape. Her answer was that the Armor she showed him was much weaker than her original which she used to get her friend Terra out of the Darkness. Once he understood that, they got to work on summoning forth his own Armor.

When they finally succeeded, Naruto stood before her in Armor that was mainly gold, black, and orange in coloration. His helmet, chest plate, and shin guards were gold in color while his arms and legs were covered in black. On his helmet were prongs like Aqua's Armor, but they were styled as fox-like ears and were trimmed with orange. His cape was rust orange, as was his visor.

When he finally succeeded in creating his own Armor, Aqua congratulated him and asked for him to let it recede into a small piece like hers when she wasn't using it. His small piece of the Armor was like Terra's; covering his entire left arm and leaving his hand and fingers bare. The coloring was black with an orange trim and a golden rounded piece that rested on his shoulder. However, Naruto noticed something different with his Armor. It was a mix of his chakra and the energy from his KeyBlade, resulting in a sturdier and self-repairing Armor. This surprised his teacher, but she was still glad that he had some added protection.

It was now what felt like a week after Naruto formed his Armor, due to their inability to determine time in the Realm of Darkness. The duo sat on the shore and gazed at the silvery moon like they had done many times before. It was nice being with one another after so long. They had easily established a strong friendship and even shared stories of their past with one another. Aqua had told him of her times with Terra and Ventus when they were still in training while Naruto told him of his early years as a Genin of Konoha. He had even trusted her enough to tell her of the Kyuubi that resided within him. At first, she was incredibly surprised and skeptical of his claim, but he was able to explain how such a thing was possible and even told her that he suspected that Kurama had become his KeyBlade. When she looked at it and remembered that it was a Nine-Tailed Fox that was sealed within him, she agreed that it was a high possibility that the fox had become Naruto's Key.

"So, what do we do now?" asked Naruto. He seemed to have aged about a year, though the two were still uncertain since they couldn't measure time. Still, his voice had become slightly more mature (1) as well as his facial features due to the loss of his baby fat. "I have my Armor now and you told me that a KeyBlade can become a Glider. Are we going to work on that next?"

"I'm not sure if you'll be able to make a Glider if Kurama is your KeyBlade, Naruto," she admitted to him sadly. She hadn't changed much during their time save for her feminine form becoming slightly more pronounced. "We may be stuck here for a while longer."

"That doesn't mean that we can't try!" he said in determination, making her smile. No matter how much he seemed to mature, that drive of his never lessened.

"Alright, we can try and see if it'll work. Although, I still don't think it will…"

"Such little faith you have, Key Bearer," came a voice that Naruto instantly recognized.

"Kurama, is that you?" he asked excitedly.

"Yea, it's me. Down here!" he called out, making them look to Naruto's KeyBlade and see the fox head grinning at them. "You didn't think you'd be able to get rid of me that easily, now did you?"

Naruto laughed at that raised the tip of his Key so that the fox could see them better. "It's good to hear your voice again, Kurama."

"Yea… Sorry I took so long to talk to ya, but I was restoring my power. But I guess you can't complain all that much considering the company you've had," the fox said with a grin.

The two blushed at the hidden message. "N-No, you got it all wrong! We're just friends, right Aqua?"

The bluenette nodded. "Y-Yea, we're just friends!"

The fox laughed at the duo and their blushing faces. "Calm down, I was just joking. In all honesty, I am glad that you weren't completely alone while you were stuck here. Now that my power is restored, I believe I could get you two out of here and to the nearest world."

Naruto fist pumped at the new while Aqua had a large smile on her face. In his happiness, the blonde grabbed the bluenette in a hug and twirled her around, making her blush at the action. When he realized what he was doing, he immediately set her down and took a step away from her with his own blush.

"Well, now that you two are done hugging, let's get started. Naruto, throw me into the air and I'll take care of the rest."

The Uzumaki nodded and threw his Key with all of his strength. When it was high enough, it was engulfed in a flash of light that blinded the two Key Bearers. When the light died down, a black and orange hoverbike was parked in front of them. It was big enough to seat two, had nine thrusters in the back, and the hood was in the visage of a large fox head. The two smiled at the ride out of the depressing realm and summoned forth their armor before they got on with Naruto in control.

"You two ready?" asked Kurama from a speaker on the Heads Up Display (HUD) of the bike.

"Ready to go!" Naruto said with a grin hidden by his helmet.

"Let's get out of here!" Aqua exclaimed happily.

The bike jerked slightly before it rose a few inches off the ground. Naruto revved the engine and the bike flew up and out of the Realm of Darkness.

The adventure had begun for the two Key Bearers.


1~ Think of his voice like that of Raiden's from the Metal Gear series (which I do not own)

And that, my loveable readers, is chapter one of a hopefully stellar story! I hope you all liked it! Please review and ask any questions via PM.

As for worlds (which I have no doubts you all are curious about), I'm going to focus on the Disney/Pixar Worlds that the KH series never bothered to add. I'll also throw in one world that is from a video game series! Hope you all enjoy it!

Next Time: The two Key Bearers arrive in their first world! Which one will it be? Stay Tuned!