Harry Potter and the Horseman of Olympus: A Harry Potter/Percy Jackson Crossover Fanfiction

Disclaimer: I do not own Harry Potter or any of its associated characters: all rights belong to JK Rowling. I do not own Percy Jackson or any of its associated characters: all rights belong to Rick Riordan. I do not own any other crossover references used in the story: all rights belong to their original creators. I do own any OC spells explained at the end of a chapter.

Plot: Wolves of War Response: A mysterious new Defence Professor was one thing, but after the Dementor attack, it's Harry himself that seems to have gone through a kind of transformation: one that will change not just Harry, but all he cares for, forever.

Challenge Information: DZ2's 'Wolves of War' Challenge: HP/PJO: Remus Lupin was reunited with Harry at the start of 3rd year...yeah, sounds about right and it would be...if it wasn't for the fact Remus Lupin is dead. So…who's this teaching Harry how to unlock his true potential and release the warrior within?

Rules: All affinities are welcome

Powerful Harry or stronger

The story MUST start with Harry and 'Remus' meeting on the train at the start of 3rd year

What Harry doesn't yet know is 'Remus' is, in fact, Ares, God of War

How Ares wound up mirroring Remus is up to you, but the real Remus MUST be dead

Sirius MUST be able to tell 'Remus' isn't Remus

When 'Remus' true identity is revealed is up to you

If Harry is a Demigod himself, he CANNOT be a Son of Ares as, after revealing himself, Ares MUST claim him as his Champion

Clarisse MUST be like a big sister to Harry

All pairings are welcome

Guidelines: Demigod-Harry

Twice-Blessed – one blood-parent, one adopted – Harry

Twice-Born/Godling – son of two Gods/Goddesses/God and Goddess – Harry

Master-of-Death Harry

Dark-Lord Harry

Ares turns Remus' werewolf form into a familiar for Harry

Ares is training Harry to be his successor – the new God of War

Other Demigods are at Hogwarts/in the HP world

Post-Percy Jackson and the Olympians

Post-Heroes of Olympus

Post-Magnus Chase

Post-Trials of Apollo

Post-Kane Chronicles

Instead of Ares, Mars or one of Ares' alternate forms is who meets Harry, but still disguising himself as Remus

Ares convinces Tom to join/serve Harry

Slash

Harems

Harry/Multi

A prophecy speaks of Harry's guidance under the God of War

Instead of a sister-figure, Clarisse becomes Harry's soulmate

Ares gives Harry a weapon as a gift – e.g. Sword of Gryffindor, Excalibur, other

Ares has a 'horse' (as in War, the Horseman)

Phobos and Deimos – Ares' sons – treat Harry as a little brother and offer gifts/blessings of their own

Forbidden: Weak Harry

Remus alive

Sirius being fooled

Ares out to manipulate Harry

Demigod-Harry: Harry as the Son of Ares, biologically-speaking

Clarisse against Harry

Anyone, INCLUDING SIRIUS, separating Harry and Ares

Harry turning down the 'training' from the man he believes is his professor

Other than that, it's up to you…

Author's Note: So, here we have an idea that explores an angle I've never read before, but…well, just see what you think, eh?

Recommended Reads: Harry Potter, Squatter by Enterprise1701-d, Harry Potter: The Prince of Underworld by Anguis Vasalias, The Son of Storms by PerseusPeverell092, Apex, Silver King and Trickshot by JustBored21, The Young Lord by SlytherinDarkHarry, Broken Shackles by Black Infinity 1289, Harry Potter, Dark Legacy by The Fallen One 2012, The Necromancer by MaeglinYedi, Worthy of Magic by Raul Fictitious, Blood Crest by Cauchy, Kill me if you can by PercyPendragon3 and The Prince Of Darkness by Writing Shop 12

Key Pairing: Dark Lunar Harmony;

Other Pairings: To be determined

Normal Speech

'Thoughts'

'Mental/Divine Speech'

/Parseltongue/

Chapter 1: Harry? Are You Feeling Okay?

Darkness.

That was the first thing he was aware of.

It was dark.

It was cold.

And he was…

Actually, he was pretty good, all things considering; as the cold and the darkness reached out to him, he reached back, albeit mentally, or perhaps emotionally, before he found himself pulled away from the cold, the dark and even his all right feelings by a sound.

One sound, which echoed through the darkness like the peal of a bell.

The sound of his name.

'Harry…'

Horseman

"Harry?"

A low groan escaped thirteen-year-old Harry James Potter as he found the familiar sensations of his body returning to him.

"Harry?"

As well as the sound of his friend, Hermione Jean Granger, calling out his name, bringing him further and further back into the light, the warmth and the realness of life. At the same time, his vision started to clear, allowing him to see his two friends, as well as the, apparently, now-awake form of one Professor R J Lupin, who looked somewhere between relieved and satisfied with what he was seeing, even as Harry looked away from him and back to the faces of his friends.

"Hey…" said Harry, slowly rising from where he guessed his body must have fallen after…whatever had just happened.

When he stumbled and staggered, however, Harry felt a small smile cross his face when Hermione moved to intercept him, holding him up carefully, which also meant Harry could feel a faint shiver run through his closest of friends. Whether that was fear, or because of what she said to him as she guided him back into his seat, he didn't know.

"Here…sit down…my God, Harry; you…you're ice-cold!"

"Not for long if you keep holding me like that, Hermione," drawled Harry, earning a superheated-red-faced blush from Hermione, while Ron scoffed.

As Harry went to direct his next words to the redhead, however, he was cut off by a loud, sudden snapping sound; out of instinct more than anything else, Harry went for his wand, though, not before he found the hand of his newest professor, Mr Lupin, offering him a particularly-sizeable slab of what he saw was milk chocolate.

"Here," said the Professor, earning a gratuitous smile from Harry, while Lupin added, "I know it sounds weird to hear, but, trust me: chocolate is the best thing for anyone recovering from being around the Dementors."

"Dementors," said Harry; he'd meant for it to sound like a question, but now he knew what they were called, the idea of them coming after him as intensely as that one on the train had done…it left a fire burning in his belly, which left his emerald-green eyes darkening, even as he accepted the chocolate from Lupin and took a big bite out of it.

"Oi! Share!" exclaimed Ron, earning a scoff from Harry.

"I'm sorry, but did you faint going up against that…that monster?" asked Harry icily, earning a surprised look from Hermione, while Ron looked like someone had just told him that the right to ask for seconds and the serving of desserts were going to be forbidden for the rest of time itself, earning a scoff from Harry. "I didn't think so, Ronald! So, wait your turn for our new Professor to offer you some chocolate, instead of whining like Dudley Dursley with red hair just because I have something you don't…again!"

"It's all right, Harry," said Lupin, earning a curious look from Harry, though, when he did so, he saw the man was smiling, almost as though he was proud of Harry's cold-toned voice arguing against Ron's latest bout of jealousy. "I've got more than enough for everyone: in the meantime, why don't you just sit here with your friends and take a few deep breaths? If you need to talk about anything, I'll be back soon."

"Thank you, Professor," said Harry, taking another bite out of his chocolate, earning another smile from his teacher.

"When it's not in lessons, like now, and when you're not in trouble with me, you can call me Remus if you want to, Harry; James was one of my best friends…Lily, too, actually, so I'd like the chance to be yours, if you're willing to let me?"

Harry just nodded, taking another large bite out of the chocolate, while he also looked to Hermione, who looked like she was still trying to figure out why her friend had suddenly turned so cold towards the third member of their infamously-popular gang.

Seeing the look, Harry snapped off a piece from his block before he handed it to her, "Here, Hermione; I know you probably weren't as badly affected by that thing as I was, but…I've known you long enough to know you were worried, so…call us even?"

"Oi! What about me?" asked Ron, earning a scoff from Harry before, to Hermione's surprise, Harry shoved his free hand forwards.

Sticking the rest of his chocolate right into Ron's mouth with enough force to choke the breath out of the redhead, while Harry scowled, "Fine, then! Here, if it'll shut you up, you big, greedy piglet: here, have the rest! Now, keep your eyes open and your mouth shut: do you think that even you can manage to do that, or should I maybe go and find another, quieter compartment, where I won't have to watch you make me lose my appetite because you can't close your mouth when you're chewing?"

As Ron actually began chewing the chocolate – and, as Harry predicted, he didn't close his mouth – Harry scoffed yet again as he shook his head.

"Oh wait…I almost forgot…everywhere else is full…right, Ronald? Guess I've got no choice, but to sit here and wait…thanks…for nothing!"

Horseman

'What's happened to Harry?'

Hermione didn't know whether to be worried, or find herself actually agreeing with Harry's long-winded remarks concerning Ronald's eating habits, as well as his desire to be anywhere but here at the moment. Even so, she was surprised by how cold, ruthless and, despite Ronald's disgusting eating habits, even forcefully-aggressive Harry was, having just nearly choked Ronald when he gave him the chocolate.

Hence the question she asked herself as, moving from next to Ronald, she decided to try and help Harry calm down again as she sat with him.

Curiously – at least, Hermione thought so – Harry's hand never left hers all the way to Hogwarts.

Although this did allow her to notice something else off about her friend.

'Why is his skin still so cold? Was it that Dementor or…or could something have happened when Harry fainted?'

Horseman

'Bloody psycho; he nearly choked me and she sits with him? Where's my sympathy? Why isn't she yelling at him? Damn, this chocolate's good!'

Not surprisingly, Ronald Weasley's train of thought was on the only things that mattered to him.

His stomach.

His ego.

His pride.

His idea of how the world should be.

And, most of all, the fact that Harry wasn't acting like the Boy-Who-Lived.

'Well, it's all right: I'll tell Percy what he did, so he can tell McGonagall, she can tell Dumbledore and then Harry will be making it up to me again; maybe I can convince him to buy me a Firebolt before I forgive him.'

Horseman

As Remus left Harry sitting with Hermione, as well as the human whining machine known as Ronald Weasley, the new Defence Professor allowed himself a thin smile as he saw how close the wise, young brunette was with the battle-hardened, death-touched warrior-wizard sat with her. The fact that even the sudden bout of coldness from Harry wasn't going to let her stray from his side was inspiring to behold.

At least, for him, it was.

However, as he left the trio, Remus' friendly, casual air turned into a look of ominous worry, as well as loathing and dark thoughts of bloodshed and suspicion, all of which caused the air around him to ripple ominously. Just overhead, as he walked along the carriageway, Remus heard thunder rumble, while sparks danced at his fingertips, making him scoff amusingly as he wondered just how much it would take for his true self to have to come out and deal with the mortals.

Especially that loyalty-deprived, gluttonous overcompensating prick who, apparently, was as good a chess prodigy as Remus' distant relative.

And yet, the guy was as thick as Tartarus was deep, cloying and Hell itself for the monsters and demons who were condemned to its pit.

'I smell a rat,' thought Remus, momentarily catching sight of his reflection in a window showing the outside world.

This allowed him to see his green eyes flash red for a brief moment as he scowled, 'Damn…I've barely had a chance to know Harry as well as I do others and I'm already showing through the cracks. Not that I have much choice either, mind you…'

Closing his eyes, as he tried to get himself centred again, Remus drew out a slow, shaky, almost-rattling breath of his own before he looked back to the compartment where he'd left his quarry with his friend and the other one.

'Now that Harry's seals are starting to break, it won't be long before others learn of him being who he really is…and then, inevitably, a whole new class of War will begin…and not one I am willing to let end in that young warrior's death, no matter what the Mortal Zeus might want to happen!'

Again, his eyes flashed blood-red, while his hands burned with a hint of electrical energy as he clenched them tightly.

Curiously, as he walked along the train, checking on his charges – as Professor Lupin was meant to do – his hands now had two oddly-streamlined gauntlets concealing the aforementioned lightning energy, their appearance so casual that they could have been described as gloves to anyone who saw them.

'Gods bless the Mist…and Gods damn the fools who think they can play God! Least of all with my young protégé…like you, Mortal Zeus!'

Horseman

In his office, Albus Dumbledore suddenly shivered in dread, mixed with a feeling of foreboding that clutched at his aged heart, making him feel something that, not that anyone else knew it, Albus Dumbledore loathed, detested and downright hated feeling.

Out of control.

Weak.

Unable to make the best of the situation for his sake.

Whoever was responsible for this feeling, Albus knew he had to make sure they couldn't interfere in his plans for a certain teenager who, now more than ever, would need to rely on the support and love of those who claimed to have his best interests at heart.

Mostly so he would be ready for the next step.

Sacrificing himself to the Dark Lord Voldemort, as the prophecy demanded.

All for the Greater Good…

Wow, talk about…well…chilling: Harry seems to be okay, but, at the same time, it's like he's cast off his rose-coloured glasses and sees things for what they really are, but how's this even possible?

Also, what could Remus mean by claiming that Harry's seals are starting to break? What will happen when they completely break?

Keep Reading to Find Out

Next Chapter: Harry seems to be doing better, if only because he has a certain someone keeping him anchored to whatever passes for normal with our hero; however, when his arrival at Hogwarts is side-tracked by an unexpected summons, Harry seems to prove, once again, that he is nobody's tool, nor is he as blind as they hope;

Please Read and Review