Disclaimer: I do neither own Harry Potter, nor the Final Fantasy VII universe. I yield no profit by writing this fanfiction, other than my own amusement.

Summary: Harry Potter unknowingly enters a pact with an evil being. Will this end in the destruction of the world? Who is this demon?

Pairing: Now that would be telling! It will certainly not be slash however.

Merge Thy Soul

Chapter 1

It was dark, That was to be expected, though, as it was night in Little Whinging. In this upstanding neighbourhood, Harry Potter, who the inhabitants of Little Whinging considered... well… not upstanding at least, lay on his bed, reading a book. If anyone living in the neighbourhood saw him, they would probably think it was something freakish, as the tome looked, and probably was, ancient and it's name was "Creaturae malae".

What kind of normal person would read a book called "Evil Creatures", after all?

Now, what those people did not know was that Harry Potter was no normal person.

He was a wizard.

A very angry wizard, to be precise, after being robbed of his godfather and then hearing of the "betrayal" of his beloved mentor, Harry Potter was in a rage. He hated Voldemort and wanted nothing more than to just end the fiend's existence and stop all of his nefarious plans.

He loathed the Order of the Phoenix. After Professor Dumbledore had told him the prophecy, he had lost control for a short time, but afterwards a lot became clearer, at least that was what Harry thought. The intricate manipulations of one Albus Percival Wulfric Brian Dumbledore, making the wizarding world believe him to be some kind of new Merlin.

He was powerful, no question, but his inaction until the key figure on his chessboard was attacked, showed, in Harry's opinion, how manipulative the old man was.

The order only sat on their butts, talking, talking and discussing "You-know-who" and his movements. This did not help a bit in his opinion. Even after the skirmish in the Ministry of Magic they went back to sitting in their dark meeting rooms and acting like a bunch of chickens.

At first, before his anger had become uncontrollable, he had tried to get his friends to lend him support, to ground him a bit.

A week after sending the letters he received one rather disconcerting answer and nothing at all from the people he considered to be his best friends.

Harry,

I can't imagine how you'd be feeling at the moment, but all of the books I've read say that you need to allow yourself to cry over him. Otherwise you will never get over it.

I'm in France at the moment, and it might be difficult for Hedwig to find me. Plus, I'm around Muggles most of the time, so please try not to send to many letters, okay? I'm sure Ron will be happy to hear from you.

Hermione

Shortly after Hermione's letter Harry received a letter from Ron, a letter that was smoking in the bin after reading just the first three sentences.

His friend's lack of sensivity led him to believe that their friendship meant nothing. In his mind, they had betrayed him.

Dudley's broken toys did not like his response.

The wizards and witches of the world were sheep; they were easily turned against anyone. All it would take was a few articles painting him in a bad light and he would, once again, be the pariah of the Wizarding World. He despised them.

The Dursleys were, of course, their usual charming selves, continuing to earn his hatred.

His once red hot rage had cooled, leaving behind a very calm, but still irrational Harry. He knew that his foolishness had cost him valuable time. So he began to study.

That was three weeks ago, he had reread his school text books for charms, transfiguration and potions from year one upwards only to discover how much theory he had missed.

Unfortunately he had not become an unstoppable force in three weeks of studying, hell, he still had problems with fourth year transfiguration, but it seemed clearer to him now.

Currently he was reading a book about dark creatures, how to summon them and such rubbish. He had taken the book out of the library shortly before the department of mysteries fiasco and had not returned it to the restricted section. He had supposed that a 'finite incantatum' was an obvious way to get past the charms on the restricted books and was right for once.

He just read about a creature called "Daemon of Hades", evil souls of perished villains in representations of their bodies, who, when summoned, would give the bearer something that was not described in any way.

There, below the description was a hand-written note. His forehead creased, what kind of information was, 'Come forth, soul of the perished, Thy eternal torment hath ended. I am willing to pay thine price. Empower me with thy gift!'

"Sounds ridiculous…", murmured Harry and then read it out once, contemplating what fool invented this fluke of a ritual..

Haaarryyyyyy Poooottterrrrr... Your drive for vengeance is... encouraging... Mother will be pleased with my find..

"What? Who's talking?", said Harry, slightly afraid of someone knowing about his plans.

I am who I am... You don't need to worry about me betraying your secrets. Are you willing to pay the price for power? To humiliate and then destroy your enemies? To make them tremble at your feet?

"Who are you? More importantly, what and where are you?" asked Harry, wondering if he had some kind of a hallucination.

"My name is of no importance to you. Be assured that I am a friend and if you did not notice, I am right her," said a male voice behind Harry, who turned around as fast as he could.

"How am I supposed to know that you are not here to hurt me? You could just be some insane plot devised by Voldemort," challenged Harry, struggling to keep an emotionless expression on his face.

"I am not here to harm you, little one, do you think you would be alive had I intended to kill you?" chuckled the figure, shaking it's head, which was surrounded by a white-silver hue.

"Prove your intentions!"

"If I had any thoughts of harming you the blood wards around this place would have expelled me immediately."

"What was the price and power you talked about before?" asked Harry, tapping his foot impatiently.

"Don't be impatient, boy! The price will not hurt you; the powers, however, are unfathomable."

"Will I be powerful enough to defeat Voldemort?"

"That powerful and more, boy," the Daemon chuckled darkly, "I swear it by mother."

"Who is this 'mother' person you keep mentioning?"

"That is of no consequence, however let me tell you that your body will strengthen and your magic shall grow."

Harry missed the look on the strangers face, had he seen it he would have started to back out of the deal very slowly and carefully. The look practically shouted: "I am evil, you will help me!"

"Will I change?"

"Do not fret, you will like it. At least after it is over. Come now, I give you a chance of a lifetime, to free yourself from the bonds of society! Throw off your leash and show them your true power!"

"Alright… I accept... I will pay the price. I will do anything to have my revenge!" a flash of light surrounded Harry and he looked around in confusion, not even thinking about the importance of his words.

"I accept your offering. You have bound yourself to accept my price. My soul shall join yours, your body shall change to a state befitting for our joint souls, your magic shall change, our souls will merge equally and we, the new ultimate being will purge the world of those that threaten us and rule the others! We shall make mother proud!" yelled the figure gleefully.

"Wait! What, No! You cant do that!" shouted a terrified Harry.

"I most certainly can, did you really think that would help you just like this? I did not lie, but I did not tell you the whole truth. We, in union, shall do as I have said and so much more!", announced the man.

In that moment a single black wing burst out of the persons back.

Harry now had his true first look at the man, as the blur disappeared. He was tall, far taller than him, well muscled and good looking. He had long, straight and silky silvery-white hair that grew down his back. .

The fallen angel held out his right hand and even though Harry tried to resist it, the binding contract and his magic forced him to shake it.

White filled his vision, and searing pain shot through his body, his mind was drowned in memories, feelings, while his magic was growing by the second.

In the cacophony of pain and uncontrolled memories he heard a voice echo:

"You may call me Sephiroth."

Here is the beginning for an idea that floated around in my head for ages.

Reviews are appreciated and encouraged of course :D