Prologue: A Key to Unlock the Door.

A few days passed, and Petunia was incredibly unnerved by the silver haired anomaly and her husband. Her husband was acting unusually kind towards the boy. While she was happy that she could take care of her sister's son, something seriously wasn't right. She would have to wait and watch.

Several weeks later, the boy began to speak. It was about the right time, maybe a little early. Things were still the same. Vernon was a little too happy, though. She tried to talk to the man, but he just replied "The boy's not as much trouble as I thought." She spoke to him again, but the man just said the same thing.

A couple years passed, and the boy started to disappear for many hours at a time. He never cried, he never complained, and he rarely said anything. Petunia and Vernon's son, Dudly, who had gained Vernon's stature, was being influenced by the pudgy man to respect and obey Harry. Petunia was still clueless. She noticed things were odd, but she was happy and quickly got used to the change in behavior. She was content.

Harry, on the other hand, was making sense of his dreams. He was now five. It started as flashes and turned into dreams. Soon it became memories that he never had. He knew theory of many things, and knew things he should not. Every day, he practiced. He made sense out of what he knew and used it to his ability. And he learned something out of all this.

He was a reincarnation.

Now, while this has been heard of, even if only in myths and legend. Nothing had been recorded, so it was all, again, theory and assumptions. And many people don't believe in this stuff.

Something with him was different. He was not just one reincarnation, but if his multiple sets of memories are anything to go by, he was the combined reincarnation of four people. Here's another thing for you to know.

Each person was from another plain of existence.

Now, this doesn't make him uber powerful. Well, I guess it does, actually. He can do things others only dream of, and has a fair quantity of power made up of several different energies. But he didn't have THAT much power or strength or speed. He only had theory and knowledge of what to do to get stronger. So, here he was, getting stronger in many ways so that he wouldn't be oppressed in any way. He had a need for power and knowledge. And he would fulfill those needs.

With that declaration, his eyes itched and changed. He didn't know that they changed, but they did. He developed a second comma in his left eye. He had already figured out what each eye did. He knew every Uchiha had unique eyes, some more powerful than others.

His right eye:

It symbolizes the power of day. Unlike other Uchihas who's eyes are filled with darkness, he has the powers of light, letting him not just create illusions, but make illusions real. At least that's what he can do now on a small scale with one comma. Only making pencils and stuff. Nothing that's alive, either.

His left eye:

It symbolizes the power of desire and control. With one comma, he can rewrite people's memories to make them believe anything. He can also crush weak people's will and take direct control of them. It also makes powerful illusions that help fuel his right eye. Now, even though he doesn't know it yet, with the second comma that he achieved from his intense desire and lust for knowledge and power, he can crush peoples' minds from eye contact and gained unparalleled control over his own mind.

What powerful eyes, no? And he knows it, too.

His Uchiha blood gave him the potential to work up insane power and speed, so he spent a lot of time working on those talents. Unlike here, where people have severe limits on their physical potential, Harry will surpass all their bounds. He had Madara Uchiha's memories, and knew how to unlock all of the sharingan stages. He'll have to kill his best friend at some point. That was… Petunia? Then, he'll infuse those eyes with enough energy to evolve them again into the eternal version, and finally the rinnegan. The other people's memories were, unfortunately still only flashes and dreams.

Today, that is about to change, in the form of a black heart of darkness.

And a key to unlock the door to potential.

Harry was walking through the forests to his training spot, about 6 miles away from the small town his 'family' lives in. I don't understand humans. They like everything to be perfect. They want what they can't have. They go and make all of the houses the same, and the only things that are different are the numbers. I think they also like to laugh at the other humans that get lost in the nearly identical houses. Weird.

So, Harry was running at a formidable pace out to his clearing. He passed the darkening trees and roots, avoiding the wildlife. There was one particularly large tree that he passed that he decided to practice his wind manipulation on and sliced through it. He also sliced through the four trees behind it.

He would have to get better at controlling his immense power.

It was a few minutes later that he appeared at the edge of his clearing. And what a clearing it was. You could barely see to the other side of it, and the beauty was profound. It was disgustingly perfect in a very close sense of the word. White flowers spread out over the expanse, with yellow ones mixed interchangeably. The sun peered over the trees like a hateful scion. Harry had no problem with light, but he hated the beauty of the scene. It was so idealistic. He wasn't an idealist. He hated idealists.

He walked out to the field, slowly. Why was he getting so worked up now? He saw a flash. Memories. He glimpsed darkness. Eternal darkness. The abyss. He saw a laboratory and several machines. A blond haired man was working. The letters DTD were scrawled on several papers. Darkness. It was all about darkness.

And hearts.

Flash. Another scene. Overpowering darkness. He couldn't control it all. It was eating away at him.

"No!" he heard himself scream. It was painful. "NO! I can't let it control me!"

And it was over. Another memory. He saw three people fighting him. No, not him. A puppet controlled by his essence. A black key. It made more darkness. It opened hearts, and released people's misery.

What was happening again? When did the next memory start and the last one end? It was all blurring together. Who was he? Where was he? He was losing his sense of self. He was destroying himself from the inside. The darkness was consuming him. But it wasn't.

He ended up staring at a door. A white door surrounded by black. A word popped into his mind. 'Kingdom Hearts.' It opened. Light came out.

And it burned. It was like falling into the sun. He screamed. He tried to shield himself, but nothing worked.

Make it stop

MAKE IT STOP!

"MAKE IT STOP!"

And he was back in the clearing. He survived. He was himself. He was everything he wanted to be, and if the price of his power was his sanity, then he didn't want it. But he was sane; at least mostly. His eyes itched again for some reason again. He'd have to check it out. He didn't want to kill for the fun of it. He would put people out of their misery and stop the evil from growing. He would stop suffering. People were innately evil, and he planned to rectify that. He saw the world from many perspectives, and knew the evil that everybody holds.

The only way to stop it was to rule this god-forsaken planet and stop that suffering himself. He would release the misery that all evil holds. With this new power, he would turn his enemies' hearts to darkness therefore destroying their misery forever. Heartless don't have misery because they're made of it. Their strength draws on the misery they had experienced in life. They can't be miserable. They can't be evil. They just are.

But, right now, he had bigger problems. Like the enormous black fire that took up the entirety of the field. There was a black cloud overshadowing the world. Screams filled the air.

Harry Potter just brought the heartless this dimension.