Hello, everyone! Lilith here.

And here we are, the third installment of the KH fanfic series: Tainted Hearts! I apologize for taking so long getting this up and running. I needed a lot of creative fuel in order to make it work.

For those of you who are new to my Hearts series, I would highly recommend reading Broken Hearts and Scattered Hearts first, and then this. For those of you who have been following me, reviewing me, and enjoying my stories, I hope you'll love this one.

All the same, constructive reviews are welcome. Rude words are not.

Anyways, without further ado, hope you guys enjoy Tainted Hearts!

I own nothing of Kingdom Hearts except my OCs.

Read, leave a review, but no flames allowed.

Prologue: A Warning to Luna

Luna. Wake up.

As the soft voice reached her ears, a fourteen-year-old girl woke up to find herself in a peculiar place that didn't seem familiar to her…or at least, she didn't think so. She looked all around her to find nothing but darkness, and was standing atop a stained-glass platform that showed the image of her, seeming peacefully asleep. However, she could tell that there was something a bit wrong about it: though she could see beside the girl the images of two boys and a girl and an elder man, on the edges of the platform, there were scars and cracks; what was more unsettling was that there were other images surrounding the picture, but for some reason they were either damaged beyond recognition or were covered by a dark substance.

Luna, a dangerous force is coming. You must be prepared to face difficult trials, face once more what broke your heart.

But do not be afraid. You will not be alone.

What was the voice talking about? She had trouble understanding what this means. Does this mean that there's something evil that could threaten the people she loves? Who will be with her during these 'trials'?

Enter through this door, and shed light as to who you are.

Before her eyes, a tall, mystical door appeared before her eyes, waiting for her to enter and see what lies beyond.

Not wanting to dawdle (and wanting to understand what this dream was about), she pushed the door as hard as she could until a light poured out and she stepped out into a large room that resembles a place she felt she once knew of; she could see a bright light fill the room through a glass window as a stairway led toward the upstairs, where three people stood at each distance, almost as though they were expecting her.

The first one she approached was a young boy about her age – maybe a little older – with ruffled, gold-blond hair, dressed in green and gray clothes with a shoulder guard on his arm and belt straps around his vest. He gave her an inviting smile, as though he wanted to talk to her.

"Ven…is it?" she asked, feeling familiarity.

"What is most important to you, Luna?" Ven asked her.

Carefully, she thought this over as she thought about what she had gained during her stay in her new home: the islands and the people who live there – even the friends and family she came to love so dearly.

"My friends…and my family…are most important to me," she replied.

The boy smiled at this. "It must be good to know you have many people who love you."

Satisfied with the answer given, he stepped aside and allowed her to proceed up the stairs to the next person she would face.

Meeting her at the top of the stairs is a young woman with blue hair and blue eyes, dressed like an elegant warrior with two sashes around her waist as well as a sleeveless top and shorts, held by straps and a brace around her chest and waist, complete with long stockings and armored shoes.

Like the previous individual who questioned her, she knew who this person was from the past.

"Aqua…?" she asked out of curiosity.

"What is it that you want most?" Aqua asked her.

Like before, she carefully thought over her answer until she was sure what was on her mind was what she wished to express. She couldn't help but think of the faces of the people she once knew, and of the parts of the strange platform she saw before; it made her wonder if something's missing.

"I want to remember who I used to know if at all, and to regain what I have lost in more ways than one," she replied.

"Is that so? Then take care not to let what haunts you torment you again," Aqua warned her in a protective tone.

After she gave her warning, Aqua stepped aside from the top of the stairs and allowed her to witness before her the presence of three thrones; one of which the last person she would meet was seated on until she approached the place that commands respect.

The last person to greet her was a man much older than her with dark hair set in a ponytail that has started to gray in several places, with a mildly wrinkled face that bore two scars over a calm yet powerful face; he was dressed more as a noble warrior, with a hakama and a white coat over his armor plate bearing the symbol of a heart on a cross.

Though she felt small before him, she also felt welcome at the same time; it was as though this person was meant to stand as a guardian.

"…Grandpa…Eraqus?" she asked nervously.

"What is it you are afraid of?" Eraqus asked her.

That was the very question she knew she could answer, but how could she bring it out? After all, she suffered enough when she lost her loved ones. She didn't want to go through the same thing all over again.

"I am afraid of losing my new friends…to the same evil that took everyone I once loved," she answered, trying to keep herself from crying.

Eraqus nodded in understanding. "I thought you'd say that. I am sorry you had to witness all the terrible things back then…"

Your friends and family are important to you. You want to remember what you used to know and regain what you lost. You are afraid of losing your friends to the evil that took away what was precious to you before.

Now, the moment of truth has arrived. Now you will be tested, to prepare you for the dangers to come.

All of a sudden, the environment changed from the grand room back into that strange place she was in; but this time, there was something different about it. She was standing atop a stained-glass that had the image of a woman with brown hair in a gorgeous yellow dress; unfortunately, she had no idea who it was.

But then, the mood changed when several black creatures with glowing yellow eyes formed out of the floor and began to search around the place for something to attack; this scared her quite a bit, since she didn't know what those things were.

You will encounter enemies that will mean harm. That is why you must fight them should you wish to move forward.

You are a Shadow Mage, are you not? You have a power not like other denizens of the dark. Your shadows are your weapons. Do you remember being taught that?

Summon the shadows to fight on your behalf.

Though she didn't know how the voice knew about her powers, nor imply knowledge she is what some call a Shadow Mage, she knew that there was no point in questioning that since those black creatures are readying for an assault. Her memories of battles she experienced flowed through her mind as several Shadow Hands emerged around her, rearing for a fight and ready to obliterate the opposition.

With just a few waves of her hands, she silently commanded the shadowy hands to slash through the little beasts while being able to remain a safe distance from the danger ahead of her; should any of those things get too close, one hand emerged to pull her into her own shadow and make a quick getaway so that she could attack from another area with little trouble. She was able to stay alive until another development occurred that she didn't anticipate.

The next thing she knew was that a much larger black creature formed from the combination of the other little beasts; unlike anything she ever saw, it was a hulking monster with tendrils on its head and a bulky look to it, complete with muscular arms and – quite strangely – a hole in the shape of a heart.

But beware: there will be other foes that appear stronger and tougher than the average foe. But you can find a way to bring them down, just as you would to any other enemy.

Though she was afraid of that monstrosity's size, she knew that she had to do something to take it down. Using her abilities, she took the time to block any projectiles that came her way, and when there was an opportunity to strike, she took it without hesitation. She rinsed and repeated this until the beast was finally taken down and it melted away into a large, shadowy puddle of some sort.

But then, without a word of warning, she watched as an individual appeared before her, sparking another feeling of familiarity. She was able to register the brown ruffled hair and the blue eyes, wearing a sleeveless top with a loose hakama and armored shoes, and leather gloves bearing armor on one side; it was undoubtedly the brother she loved but lost to forces she couldn't stop years before.

You once had someone who you cherished so much.

She watched as the young man turned to face her, and was about to reach a hand out to her; but the darkness below surrounded him until he disappeared from her sight.

But then you lost him.

Then, to her right, she saw another person appear before her eyes. She was able to recognize the silvery blue hair and the aquamarine eyes she had known ever since she lived on the islands, which let her know that it was Riku she was seeing. She watched as he extended his hands out to her, as though he wanted her to come to him.

Do you want to save another person you love from suffering the same fate? If so, then you must fight that which threatens your loved ones like they did before.

She tried to move forward to take the inviting hands into her own, but she couldn't move. Why was that?

But beware, Luna.

Another figure formed out of the darkness over to her left, but she couldn't tell who it is since that person was dressed in black, and had their face concealed in darkness; however, she could tell that this figure was a man, but who exactly? She didn't know.

The male figure extended his hand out, as though he wanted Luna to come to him without question.

There are others who will stop at nothing to take you, and make you theirs.

Before she could make any movements, she felt herself being pulled into the darkness with no chance to escape. But before she vanished into the shadows, the voice gave her a small reassurance against her fears.

But do not despair, child. There is always a light to guide you through your ordeals.