This fanfic is a crossover between the Harry Potter book series and the Danny Phantom AU "Time's Apprentice" by Atrieisan on deviantart (check out her comic - her artwork is beautiful!)

This is only Arc 1 of 3, but all of this arc has been written. So you can expect regular updates every Wednesday until Arc 1 is finished! You can find this fanfic here, as well as on:

ArchiveOfOurOwn (Ciestess)
Deviantart (Ciestess)
Tumblr (CiestessDE)

Also, if you like my writing, you should check out my other series "One-Shot Wednesdays" where I write a requested short story every week! I'm also in the process of writing an original book series called "Crossroad of Infinity," so if you want to know more about that, you can check out my Tumblr (shown above).

Finally, I want to thank everyone who helped beta this story, including Jay. Bloodworth (jaywrites101 on Tumblr).

I hope you enjoy!

Ghost Zone - Clocktower - Sometime in the 2000s

After the accident that transformed him into a dangerous creature known as a "phantasm," Danny had been staying with Clockwork, the Keeper of Time. The ancient being had saved Danny many times, and in many ways, by then. He'd even taken Danny under his wing as his apprentice.
And as his apprentice, Danny was often sent on missions - either by the immortal Keeper himself, or by his bosses the Observants.
It was one of these missions that Danny was currently trying to find out more about.

"Why are these things so much trouble, again?"
Clockwork was floating around the room, his purple robe and spectral tail flowing behind him, working on making his apprentice a few extra batches of imitation ecto-energy, or "substitutes."
Just in case Danny ran out while on this mission. (Not that Clockwork was trying to hint at anything… Because honestly, if he did, it would just make things worse for the poor boy.)

"They are only trouble if they fall into the wrong hands. I had planned to discreetly destroy them myself, but…"
By the way he trailed off, Danny knew he would never get the end of that sentence.
"Alriiiight… So are you at least going to tell me why you're sending me to a MAGIC SCHOOL first?"
Silence.
"Aaarrrgh!" He bumped his head against the nearest wall. "*sigh* Fine. Whatever. Why do I even bother asking questions, anymore…"
Clockwork handed him a large backpack with the substitutes in them (all 3-years-worth… And, yes. It WAS heavy), and, after Clockwork formed his legs once more and retrieved his staff, they walked in silence to one of the innumerable clock-shaped viewing screens.

Clockwork twisted a few mechanisms on his staff and waved it in front of the screen, and, with a sound like tv static, a view of a dark, mysterious forest appeared on it.
"Y'know, just because no time will pass HERE, doesn't mean it will feel like it to ME."
"All you need to do right now, Daniel, is stay focused on your mission. And remember, the-"
"'The Lions with the time-turner, lightning-bolt scar, and hair like fire are friends; watch out for the rat; and the black dog is not a threat.' Yeah, you've only repeated that a few dozen times today."
Clockwork stepped out of the way of the portal, and Danny flew through.

Despite knowing the most likely outcome (and having a backup plan for all over-fifty likely dangers), he couldn't stop himself: "... Be safe, Daniel."

Hogwarts - Forbidden Forest - 1993

As expected, Danny had arrived above a forest and about a mile away from the school in the late morning. He took his time flying, and, after a few minutes, he was about halfway there. At this point, he decided he should probably go ahead and take one of the substitutes, seeing as it had been a while since he last ate.
But as he was about to uncap the bottle, he noticed a strange black shape moving toward him from the school's direction. It was moving rather quickly…

He could feel his hackles rising from the aura the creature was giving off and the way it made the space around it darken. It was too close, and coming in WAY too fast.
He managed to get the bottle back in the bag, but he didn't notice the OTHER of the creatures come up from below him in time. It knocked the bag out of his hands before it-

Pain. Electricity. Screaming.

The creature shrieked when the blast of ethereal fire hit it. But, although he'd fended off the one, its buddy was only a few feet away now.

Danny picked up speed - still trying to get to the school - before realizing how much weaker he felt.
'Those things must feed off ectoplasmic and ethereal energy. But how? What are th-? OH!'
Now he remembered: Dementors. They were Spirit Eaters, just like phantasms like him. Except they usually only fed off of emotions.
'So why do I feel weak? … Wait, I feel wea- The substitutes!'

Danny turned around to try and find the bag and the (hopefully not broken) bottles of imitation ecto-energy, but the dementors were done only trying to snack on him.
They were still starving, but anger and ages-old hatred between their kinds had overruled hunger. If Danny slowed... they would destroy him.

So Danny flew.
And he fought.
And he became weaker and weaker, and - eventually - hungrier and hungrier.
And by the time the wizards showed up, he was starting to fall apart...

Hogwarts - Defense Against the Dark Arts (DADA) Class

Professor Remus Lupin was writing on the board in silence, finishing his final preparations for the day's lesson, while the third-year Slytherins and Gryffindors - including the Golden Trio themselves: Harry Potter, Ron Weasley, and Hermione Granger - settled into their seats. But while the rest of the class were preoccupied by today's lesson, the latest gossip, or a forgotten textbook, Hermione…

"Professor? Could you tell us a little about phantasms? They were only briefly mentioned in the book."
She continued to flip through her textbook until finding the page in question. A brief paragraph greeted her with the challenging lack of information that had left the brunette in an absolute storm of frustration, no matter how many times she went over it.

Remus Lupin, dressed in his usual ragged robes, turned his gaze to her with a mixed expression. His normally sad, wistful smile fell, and a sigh left his lips.
But his tired eyes brightened at the topic, as a hand brought itself up to rub his furrowing brow in thought.
"You bring up an interesting topic Miss Granger. The little information that is written - is true to the fact that there is little known about them."

The class was silent, waiting to sate their curiosity.
Despite the numerous times most of the students would simply roll their eyes at 'Know-It-All' Granger's antics, this was something even many of the pureblood Slytherins in the room hadn't heard of. All ears honed in to hear the professor's next words, hung with anticipation.

"From what little we do know, I can tell you that phantasms are very rare creatures of the spectral class. Not unlike ghosts or poltergeists with their varied appearances and personalities; and yet they hold a frighteningly close similarity to dementors in the dangers they pose. They are, indeed, Dark Creatures."

Harry shuddered as the rest of the class broke into nervous murmurs. Snickers came from some of the Slytherins, followed by teasing gestures imitating dementors aimed at Harry. The raven haired teen just gave a huff in response, turning his attention back to the professor, while Ron continued to glare at Malfoy and the other Slytherins. Hermione then broke the moment of tension and returned the eyes of the class to their professor.
"How is it possible for a ghost-like creature to also be a dementor-like creature?"

Lupin pondered her words for a moment, his mind attempting to piece together the few existing bits of information regarding the matter.
"In that lies the mystery. From what little is known, we can only piece together a few facts, considering that they are, in fact, corporeal beings - unless they wish otherwise - and are extremely aggressive in demeanor."

It was Ron's turn to earn a few points for curiosity, "But if they're so aggressive… how come almost no one's ever seen 'em?"
"Good thinking on your part Mr. Weasley, though that in itself brings up more questions than answers. As your book states, many old stories of ghost attacks or hauntings are results of phantasms holding claim to their territory. More often tormenting muggles and going out of their way to avoid the wizarding world."

This brought another snicker from the Slytherin group. Malfoy leaned back in his chair and shared a cruel smirk with some of his housemates.
"Seems there's actually a respectable creature out there after all."
More bits of smug laughter came from the group at the implication their 'leader' had made.
The weary teacher cleared his throat to grab the attention of the students before a fight broke out.

"They're not to be taken lightly, Mr. Malfoy. Most reports of attacks - from the few who have survived - have been upon unwary witches and wizards that stumbled into their haunts. Despite their preference to muggle neighborhoods, they will not differentiate when it comes to what they claim as their territory. Though I have not met one personally, from what I've heard, they can make even a dementor look docile in comparison."

The class fell silent once more with the weight of the professor's words. The meaning in his tone was clear: This was not a matter to be taken lightly. The silence was only broken by a nervous squeak from Longbottom.
"P-pp-professor…. Are they….. r-really that dangerous?" Neville chirped, his body attempting to sink below his desk.
"Indeed. They are one of the few dark creatures that dementors will respond to in earnest - and violently for that matter. Usually the two species will avoid one another, but should they cross, a fight will undoubtedly occur.
"It is also said that their presence can often be mistaken for that of a dementor's, as the room will become as cold as ice. But rather than the happiness being drained out of you, a sense of feeling hunted will settle in your gut… "

And right then, what would have otherwise been an inconsequential lesson - doomed to be forgotten except for the occasional nightmare or horror-story - became a well-timed joke for the old, meddling Keeper of Time.

Lupin found his words cut short as his gaze turned towards the window in surprise. Every pulse in the room raced, adrenaline pumping through them to prepare them to fight or run - but a feeling of despair soon layered on top, competing with this sudden desire for life.
Harry, Ron, Hermione and the others, turned in the direction of their professor's gaze; expressions of fear, horror, and curiosity forming upon their faces, as all eyes fell upon the window glass.
Crystals of ice crept up the window panes like an all-consuming fungus, encrusting the view to the outside world in a layer of frost - just as a black figure flew by, followed by another two, much larger, forms. Gasps rose from the crowd of students as they darted over to the window to see the spectacle that had just raced by. Professor Lupin pushed his way to the front of the group, peering out the frigid glass towards the scene playing out less than thirty meters from them.

Two dementors encircled, and were lashing out randomly at an unusual entity. A teenage boy, not much older than Harry or the others, floated there in the middle of the two wraith-like creatures. He was dressed quite oddly: a long-sleeved black shirt and black pants; white boots, belt, and gloves; and a sleeveless, white hoodie. His snow-white hair hung down into his face - but it didn't hide the blazing green glare and bared fangs the boy directed at the two dementors.
Just as they lashed out again at the floating boy, a yelp rang out from most of the class. A flash of neon-green light had tumbled one of the beasts backwards! However, it quickly recovered from the intimidating attack, and all three specters shot off across the grounds - the two dementors remaining in hot pursuit of the ghost-like boy.

Hermione was the first of the class to recover from the shock enough to speak; her gaze turning from the window, to Professor Lupin, and back again.
"Professor, was that… ?"
Remus remained in stunned silence, staring out the window in his own spell of disbelief. However, quickly shaking himself from his thoughts, he turned to face the students.
"So it would seem. Class is dismissed - and I want you ALL to head to your houses immediately! I must speak to Professor Dumbledore."

Hurried footsteps clattered down the stone corridors as students and teachers alike scattered about. The Golden Trio darted through the crowd and over to the nearest window that viewed the grounds. Soon followed by the Weasley twins, who'd spotted them slipping by.
"Wotcher, Harry! This has to be one of the weirdest sights Hogwarts has seen, 'eh?" George grinned, patting the raven haired teen upon the shoulder, as he and his twin peered out through the glass.

A black-and-white speck went whizzing by the gamekeepers hut, with the two other figures in hot pursuit. The extremely large man that resided in the hut could be seen exiting and flailing up at them in agitation.
"Hagrid!" Harry jolted, looking ready to leap through the window and save the man from the angry specters.

"Easy now, Harry. I think we best let the professors handle this one." Fred had the same grin as his twin, his hand coming up to pat Harry's other shoulder.
"Yeah, even the professors are gonna have trouble with this," George chimed in. Harry heaved a sigh in response.
Hermione shook her head, "I just hope Professor Dumbledore knows enough about them to do something."
Ron was about to smack himself in the face at her comment, but stopped when the scene swept by the window. The blur of motion caused him, and several others, to yelp in surprise.

Outside the Entryway

"Merlin's beard!" Professor McGonagall swore, a hand held to her chest to steady herself from shock. The three specters just whisked by centimeters from the tall, severe-looking teacher's head as she stepped out onto the grounds.
Her eyes followed the scene fly out across the lake and back again. Her gaze then shifted over towards Dumbledore, who had just arrived in the entryway of the castle.
"It's trouble enough just having dementors around the school grounds, but in Heaven's name! This is too much, Headmaster!"
The old wizard chuckled, his piercing blue eyes twinkling behind his half-moon spectacles.
"There, there Minerva. This will be settled soon enough. But first, it would be best to separate them before this matter escalates. Severus?" Dumbledore turned to look back up the stairs, a serious look on his face as blue eyes met jet black.

"Yes, Headmaster?" The thin, sallow-skinned man remained stoic, his tone flat with a hint of irritation. Although it was likely due to general frustration (with the DADA professor), rather than with the situation at hand.
"If you would?"
Professor Snape nodded, his wand at the ready for the creatures' next pass. The group of professors (as well as the unavoidable huddle of students behind them, just inside the entryway) watched the creatures' exchange nervously.

As they flew, the black-and-white blur would sporadically fire green projectiles at the following dementors, causing one or both of them to briefly fall behind. They sped over the lake, the Forbidden Forest, and made several laps around the castle once again, before coming within reach of Snape and Dumbledore's wands.
"Expecto Patronum!" yelled the Potions Professor, successfully blocking the dementors' pursuit.
At almost the exact same instant the Headmaster cried "Irretio idolon!"

The boy-like apparition immediately fell, as though snagged on a line. When he hit the ground, there seemed to be a physical struggle - as though the phantasm were trapped in an invisible net held together only by the tip of Dumbledore's wand. Once he regained his bearings, the phantasm tried to fly away again.
The old wizard wasn't expecting the smaller creature to be so strong; before he knew it, Dumbledore was pulled a couple meters forward. He quickly started shaking and sweating from the strain of trying to keep the phantasm in place.
"Pomona!"
The dumpy, dirt-covered Herbology professor quickened her pace from the Greenhouses, carrying a sack of what resembled roses in one hand and glowing green dust in the other. She carefully combined and formed these into a circle around the phantasm, being sure to stay well out of striking range. When she finished, Dumbledore immediately released his hold on the spirit.

Professor Sprout fell back in fright when the phantasmal boy sprang at her, fangs bared and growling so low she could feel the ground vibrating beneath her. She breathed a sigh of relief when the barrier held.
Everyone took a few moments for the shock to wear off, before Hagrid approached Dumbledore. "Wha' should I do with…"
Dumbledore shook his head, "I'm afraid, Hagrid, that this will take the care of professionals to be dealt with safely."
"Ay, ay, Headmaster, sir."

"And who, may I ask, has the most unfortunate job of supervising the creature until such professionals arrive?" asked McGonagall.
"I believe that falls to whomever is most familiar with and knowledgeable on such matters." His eyes, duller than usual (though not by much), turned questioningly to the other professors on the stairs.
Remus stepped forward. "I suppose that would be me… Though I'll need at least one other to help me, as I can't be watching it at all times."
"I'll take the night shift, professor, don'tcha worry none," said Hagrid, "I've ne'er met a creature I couldn't take a liking teh."
"Yeah," whispered Malfoy, near the back of the huddle of students still just inside the doors. "But I've never met a creature or wizard who could take a liking to that oaf. Except blood-traitors and mudbloods."

The Heads of Houses quickly began ushering students back to their dormitories after that, and the search began for how such a dangerous and powerful creature had managed to come so close to Hogwarts without being detected by the castle's barriers.
And that evening, in a corner of the Gryffindor common room, a certain group of students discussed how they could use this situation to learn more about the elusive creatures called "phantasms"… as well as whether, and how, this might give them a new way to fend off the ever-lurking threat of the dementors.