A/N: Let's see how this goes, shall we?

Summary: Dark has left Daisuke now that the young man has his sacred maiden, but where does that leave Dark? His destiny is not over yet and it has something to do with another boy's incredible fate. DN Angel/Harry Potter crossover.

Chapter 1: Dark Dementia

Dark woke up with a sense of confusion about him. He was supposed to be sealed, sleeping for eternity along with Krad after what should have been the final battle between them. The Phantom Thief had left the world to Daisuke to live in and now he found himself waking up to a body laying on its back on the ground, the heat of summer beating around it. He watched through this new host's eyes, trying to gain a clue to where he was, but only saw a bush to one side and the wall and open window of a house to the other. The sounds of what he supposed to be a television flowed out the window and down to him.

His host body brought a hand up to his head to wipe sweat from his brow and Dark looked at the pale, slender arm of a young man. He was very skinny, Dark noticed with annoyance, even more skinny than Daisuke had been. As the hand brushed across the boys forehead Dark took in the feeling of tufts of hair clinging to the sweat drenched skin and something hard that he recognized as glasses. On further examination of the ghost sensations he got from his host, he found that he wore baggy clothes and something dug into his side slightly from the waistline of his pants.

"…Glad to see the boy's stopped trying to butt in." The voice came out through the window Dark's host body lay under. The sound of it made Dark sneer and his feelings of contentment only deepened as he felt a responding annoyance resonate from his host.

"Where is he, anyway," the voice came again.

"I don't know," another voice replied. This one sounded uptight and disinterested, as if the subject they were discussing agitated her. "Not in the house."

The feelings that seeped through his connection with this boy allowed him to assume that the boy they were referring to was the one he shared a body with now. Dark wondered what kind of life his new host had if he was being called "boy" instead of his real name. This brought up the question that had been at the surface of Dark's mind since he'd figured out he was once again in a body. Who was this kid? He couldn't just keep calling him "the host body". A split second after the question was acknowledged Dark felt the answer jump to his mind.

Harry Potter

Dark noticed with surprise that it was the boy's thought that replied back. He froze for a moment, wondering if Harry knew he was there already but the boy didn't seem to notice that he'd answered Dark's question, or that the question had been asked in the first place. He merely listened intently to the news that suddenly chimed in on the television. Dark listened too, trying to figure out anything he could about the world he was in. There was nothing interesting to him though and it didn't seem to interest Harry either as he closed his eyes against the fading summer sun. He then cautiously moved to his knees to leave.

What happened next left even Dark in a swirl of confusion for a moment. A resounding crack filled the air sending Harry springing to his feet and something to crash inside the house as someone screamed in surprise. Harry's head collided with the open window and Dark winced as he felt the pain of the impact through their connection. Dark groaned.

This boy is as clumsy as Daisuke…

Harry's eyes began to water but the boy had already pulled out whatever had been digging into his side earlier. The tingle Dark felt in his own hand brought his attention to Harry's corporeal hand that grasped what appeared to be a stick. On closer inspection, he saw the expert carving of it and felt the power that seemed to sing from its center.

This is like the Hikari art, Dark thought. Why does Harry have something like this?

At this point, Dark noticed something responding in Harry's own body. It seemed as though this artifact was like a key that opened the door to whatever was flowing through Harry. It was magic, this was as much as he could tell, but it was different than what he was used to dealing with. And to add to it, he'd never shared a body that had its own magic at this level. Daisuke had been the first of the Niwa family to use art as the Hikari family had and even then it wasn't the same as this. He'd have to ask Harry about this once he finally made himself known, but now wasn't the time as he suddenly felt meaty hands grab Harry.

"Put it away," Dark now had a face to go along with the voice that had grated on his nerves only minutes before. It was large and very chubby with beady eyes, and currently purple with anger. "Now, before anyone sees."

Harry was having difficulty breathing from the tight grasp around his neck. Dark could only watch in anger, as coming out now could mean more trouble for the boy. Harry told the beast of a man to get off of him, struggling while still clasping tightly to the magic artifact in his hand. The injury to Harry's head throbbed through their link and at that moment something strange happened. A surge of magic passed through Harry and with a yelp the ugly man released the young man. Dark watched the scene with interest, knowing that the boy hadn't done anything with his magic artifact and yet his magic had been triggered.

On the release of Harry's neck, he fell panting on the bush he'd been hiding behind and then straightened up to look around at the street. He was looking around for whatever made that sound. Several people were gazing out of their windows now, curious and annoyed by the racket outside their homes. The meaty man laughed it all off, and said something about a car back-firing.

Car back-firing? That wasn't a car, Dark thought and he found his young host thinking along the same lines. He attempted asking Harry a question, hoping the same thing would happen as before.

What was that noise?

Someone apparating…

This left Dark with more questions but he assumed it had something to do with magic, and he was right as he stretched out his senses. The air had a smell about it that he associated with when a magical artifact had been awoken or after he or Krad cast spells. It was rather weak, which indicated it was further away and already dissipating.

"What the devil do you mean by it, boy." Dark was brought back to the moment as the annoying voice spoke again. When he looked, the large face was still furious as the man bit off his words.

"What do I mean by what?" This was the first time he heard Harry's voice spoken out loud. It was one of a teenager, obviously, and it sounded both annoyed and distracted at once. Harry kept looking around him, trying to find whoever had "apparated" as he called it. This didn't seem to calm the man in any way as he continued berating the boy.

"Making a racket like a starting pistol, right outside our…"

"I didn't make that noise." Harry's voice was firm and angry at the man's accusations. A woman then came up beside the man, the complete opposite of the man's wide figure and resembling a horse as she joined in the argument. Dark became disinterested in the exchange after awhile, only listening in when the man and woman mentioned something about Harry's "lot" and owls delivering news. He then chuckled as Harry threw their words back into their faces and stormed off. Harry soon made a beeline down the street and came to a park that looked to have been vandalized recently. He had glanced back several times on the way there, looking to see if anyone followed him and Dark couldn't help thinking he was a little paranoid for his age.

Don't think about that…

Dark jumped in surprise as the strong thought came from Harry. For a moment, he thought Harry had heard him but the ghost of a memory was fading from the young man's mind that told Dark he wasn't. The picture had been of a graveyard and Harry himself tied to a tombstone as a dark figure bent over him and Dark understood why the thought had been so loud. This wasn't a pleasant memory. Dark frowned, quickly re-evaluating his image of the boy.

Harry sat down on a swing, one of the few that hadn't been broken, his mood not improving. Dark could feel the frustration and restlessness coursing through Harry's veins. It didn't seem to improve, but rise in anticipation when a group of burly boys rounded a corner. Harry stared intently at them, seeming to pick one out of the gang in particular. He looked very much like the ugly man that had grabbed Harry earlier except he actually had some visible muscle to him.

Look round, Dark listened to Harry say in his mind, Come on, look round. I'm sitting here all alone. Come and have a go.

The boys didn't though and Dark felt a relief that they hadn't. He hadn't seen much of Harry's figure but he knew the boy was far skinnier than those boys and wouldn't be able to take them on if they attacked him. Harry's thoughts had been suicidal, something Dark attributed to Harry's current restlessness.

…Nothing rash, kept my nose clean…

Dark caught this piece of Harry's next thoughts and couldn't help smirking at the boys brooding thoughts. He couldn't resist by now, and Dark responded while his smirk broadened.

It's a good thing you didn't get in a fight, you know. Those kids would have crushed you.

I don't care, came Harry's reply. The young man then froze as the realization that the previous thought hadn't been his own. Dark resisted laughing as he looked around at his surroundings

You're looking in the wrong place, kid.

Where are you, show yourself. Harry's hand was creeping towards the wooden stick and Dark allowed himself to chuckle.

Are you sure you won't me to show myself? It won't be a very pleasant experience for you.

Show yourself… Dark sighed.

Don't say I didn't warn you. He technically had permission so Dark moved to take over. The first transformations were always the toughest for his hosts, as it was a surprise for them, but Dark knew that if he didn't transform he wouldn't be able to convince the boy he was there to help. Harry's muscles tensed at the sudden pain that transforming brings and doubled over. Dark felt larger muscles fill out the body and limbs lengthening as his mind came to the front and Harry's was pushed back where he had previously been. Dark blue strands of hair fell into his face and Dark finally stretched his limbs as he gained complete control of them.

"This feels great," Dark said out loud, continuing to stretch. A satisfied smile played on his lips as he stood up from the swing. His view point was about a head taller than Harry's had been and Dark could just see over the top of a house fence in the distance.

What's happening? What did you do to me? Harry's voice in his mind was panicked and he practically shouted as he tried to fight back to the surface. Dark winced at the volume and fought against Harry's struggling as he tried to talk to the boy. He was having difficulty though, as Harry seemed to be focusing on getting out and his mind control was strong.

Let… Me… Out!

I'm not here to hurt you! Will you just listen to me?

I don't believe you! Harry continued to fight and Dark was finding it harder to resist.

Look, you're the one who wanted me to show myself in the first place so I suggest you calm down and listen.

How do I know you don't work with Voldemort!

Who? He felt Harry's struggling settle a little and he had an idea that it had to do with him not knowing this Voldemort. Dark tried once more.

I only want to help. Please. Harry stopped and for a second Dark thought he'd blacked out before the boy replied.

Who are you? Dark smiled in relief, brushing a hand through his messy blue hair.

I am Dark Mousy, Phantom Thief to some.

Phantom Thief?

I steal artwork, magical artwork to be more specific.

Magical… The image of a large portrait of a fat woman wearing a pink dress rose to the surface of Dark's mind from Harry's thoughts. The woman moved around in her picture frame, much to Dark's amusement.

Interesting, but not that kind of magical art. The feeling of surprise and embarrassment came through their connection as Harry realized that his thought had been seen by Dark and the phantom thief laughed out loud. This sparked annoyance in the young boy and Dark settled down to explain more.

I steal artwork and artifacts that may pose a threat to people and seal its magic. Harry mentally nodded his head in understanding.

Why are we…

Sharing a body? He again nodded his head. I technically don't have a body of my own, so I need a host to share with. When you are in control, you are in your form. When I am in control, it becomes my form.

Why me? The words sounded both as if they were a question for Dark and a pleading to whatever fates that got Harry into this. Dark couldn't help smiling sympathetically as he shrugged.

Beats me. I wasn't supposed to be sharing a body anymore.

Wh… Harry's words were cut off as Dark tensed. What is it?

I don't know, but it's close.

Dark quickly headed in the direction he felt the feelings most strongly from. He vaulted over the park fence with ease and hit the ground running. His speed brought him soon to a street that was empty save for one of the boys from the group that had past them by.

Dudley, came the name from Harry.

You know him?

My cousin.

That means… Dark thought back to the fat man and his horse like wife. He scowled at the realization that these were Harry's relatives.

You'll have to tell me more later. That thing's getting closer.

A chill went down Dark's spine as he suddenly stopped, feet away from Dudley, and listened intently. Dudley stopped too and turned around to see Dark standing there. His beady eyes narrowed at the taller, older teen.

"Who are you?"

"No time for introductions," Dark said as he suddenly felt the chill increase and his hearing picked up a rattling breath. He broke into a run, straight for Dudley who now blanched with fear. Dark smirked at this before pushing off the ground to go soaring over the fat boy and towards what had been moving up behind him. It was darker than before, too dark, and he attributed this to the presence of this creature. He could vaguely make out its dark outline though and as he moved closer towards it he felt Harry gasp.

Dementor! Dark, don't!

The warning was too late as Dark collided with it. The contact was a shock to Dark's system. If it had been cold from a distance, it was like being suddenly frozen from the inside out right next to the being. Dark pulled away from the creature, landing roughly on the ground below it as he caught his breath.

What kind of creature is this? Harry? Harry wasn't responding though. Dark shouted his name and there was a slight rustling in him as Harry seemed to pull himself up to speak.

They suck all the happiness out of you, leaves your worst memories. Dark grimaced at how weak Harry sounded.

Is there a way to fight them? Harry, answer me!

Patronus… Harry seemed to be falling back into unconsciousness but his mind still brought up an image of a stag of light. Dark concentrated on the image for awhile before nodding his head.

"Looks like I'm going to have to try something new." Dark pushed himself up, a crackling ball of energy materializing in his hand. His senses suddenly took in the approach of more dementors and his eyes narrowed in concentration. He brought in his hand to his chest, building up energy and then releasing it as his hand shot out once more. The ball expanded and then exploded in a ripple effect. The waves of energy caught the dementors and sent them fleeing with an unearthly shriek.

Dark brought his hand back down to rest at his side, flexing it as he let the energy ebb away. He felt Harry stir and Dark closed his eyes to concentrate on the boy.

Harry, are you all right?

I'll be fine… How- How did you do that?

It's my expertise. Though, I'd have to admit, I've never come across something like that before. Harry gave him a more detailed description of dementors and Dark listened with interest and feeling a little sheepish as he got to the part about how thy affected people. Dark massaged the back of his neck, sending apologetic feelings through their link.

I guess I shouldn't have gotten so close to the thing, huh?

Where's Dudley? The question brought Dark out of their little world and back to the street he was standing on. He turned around to where Dudley had been standing before and found the large boy not too far off, curled up on the asphalt.

What's up with him?

I don't think he took the dementors too well. Muggles can't see them but they can still feel them.

Muggle?

Non-magical humans. I'm a wizard. That explained a few of Dark's other questions. He moved closer to Dudley, to find him whimpering softly. Dark nudged him with his foot but his condition didn't seem to improve.

I think we're going to have to carry him, came Harry's annoyed voice, followed by an exasperated sigh. Dark nodded in agreement, grimacing at the bulk of Harry's cousin. He leaned over though and hoisted the boy up to his feet.

"Come on, snap out of it and walk." Dudley didn't seem to hear him but his legs began to move on their own. Dark put one of the boy's large arms over his shoulder and helped guide him towards Harry's house. The sound of feet pounding the pavement as someone ran towards them made him stop and he almost lost his balance as Dudley tried to continue walking. Dudley fell to his bottom and Dark watched the curve of the street intently. A frazzled looking old woman came running around the corner, grocery bag swinging wildly and clanking loud enough to wake the neighborhood. Dark arched his brow, looking at her quizzically.

That's Mrs. Figg, our batty neighbor. She must have seen something.

Mrs. Figg, by this time, had reached their part of the street and stopped, panting and looking furious. She then straightened when she took in the two young men in front of her.

"You're not Harry!" Her voice was full of surprise as she looked between Dark and the slumped figure of Dudley. "What are you doing with his lump of a cousin!"

Dark laughed, both at the woman's reaction and how she'd referred to Dudley. She watched him warily and raised her arm holding the shopping bag, as if reading herself to swing if he were a threat.

"I'm just taking him home." Mrs. Figg's eyes then darted about in a panic.

"Where's Harry, where's…"

"Harry's safe, and if you're wondering where the dementors are… don't worry, they're gone."

Dark, no. She doesn't know about… Harry stopped when he noticed that instead of confusion, Figg nodded as if she understood. She still looked angry and worried as she started walking past Dark in a hurry.

"Come along with the boy and follow me." Dark listened and picked Dudley back up, moving to follow behind Mrs. Figg. She was heading towards Harry's house. She briefly glanced back at Dark to yell again.

"Where's your wand for heavens sake?"

"My… wand?"

"You're an auror, aren't you," Figg asked briskly. "Something else might come along! Never mind the statute of secrecy now. Goodness, they aren't training them like they use to…" Dark stopped briefly as the woman continued down the road, mumbling to herself.

She thinks you're an auror, magic police. Pull out my wand.

"You mean this?" He pulled out the wooden artifact and looked at it. It gave off a similar tingle, like when it reacted in Harry's hand.

Yes, hold it out so she doesn't yell at you again.

Dark held it out in front of him, feeling ridiculous as he had no idea how to use it. If anything came along, the best he could do would be to use it like a sword but he had a feeling this wouldn't be very affective on magical creatures.

"Keep walking, boy. We need to inform Dumbledore." Dark resumed walking, feeling more ridiculous by the second until they reached the house. As soon as they stopped, Dark let Dudley drop where he was which happened to be the lawn of Number 4 Privet Drive. Mrs. Figg was currently fuming about someone named Mundungus Fletcher when a cracking noise broke the night air and a man materialized before them.

So that's what apparating is, thought Dark as he watched the man get into an argument with the seething Figg. He was dirty, wearing tattered clothes and smelling strongly of tobacco and alcohol. Figg was currently berating him for leaving his post and Harry was taking in the scene the same as Dark, trying to figure out what was going on.

Mrs. Figg must be a witch or something. It's the only thing that explains anything. What was that man doing outside my house though…

We'll worry about it later. Now's the time for me to get out of here…

"… And if it hadn't been for this auror, Harry's cousin could have been kissed! Someone could have died, Mundungus. Get that through your thick head…"

"What are ye talkin' abou', Figgy?" The man's words slurred as he looked around Mrs. Figg at where she was pointing. "I don't see anyone but tha' cousin of Harry's."

Mrs. Figg spun around to find that his words were correct. Dudley lay on the ground, whimpering slightly still, but there was no trace of the young man who'd help carry him there. The old woman paled slightly.

"Dear Merlin…"

A/N: Well, that was interesting… Review please!