AN: Hello all my name if Greed720 and this is my first story for this kind of crossover. I decided to do a crossover between RWBY and Percy Jackson. This is mainly because I think such a crossover would be interesting, and also because there is a lack of such crossovers at the moment.

This story will feature an AU Percy. His history will follow canon up until the book the House of Hades, and then things will be different. These changes will be shown as the story progresses. Other than that I hope you all give this a chance and enjoy it.

I would really appreciate any feedback people would be willing to give me, as I find reviews are very useful when it comes to improving upon both your writing and your story.

Disclaimer: I do not own RWBY or Percy Jackson.

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Chapter 1

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(In the Emerald Forest, Remnant)

When Percy finally came to, the first thing he saw as he opened his eyes and pushed his aching body up into a sitting position was a thick canopy of trees. Through which he could just about see the bright beams of moonlight shining.

"What in Hades…" Percy groaned to himself as he tried to push himself to his feet, failing halfway as he collapsed back to the ground. His hand giving away beneath him as a sudden wave of tiredness hit him.

Letting out a grunt of irritation, Percy gritted his teeth and used both of his aching, shaking arms to push himself up. Everything ached, from his arms and legs to his back and head, it felt like he had just been standing at the epicentre of an erupting volcano. Before being propelled halfway around the world by the blast. Some people may think that is a bit of a weird analogy, but the sad thing is Percy had been through such an experience before. So he knew the bone weary ache well enough to make the comparison.

Slowly he rising to his feet, Percy shook his head trying to get rid of the dull ache that seemed to have settled there. Closing his eyes Percy began to draw on the moisture in the air, drawing it to him and surrounding his body in a thin film of water. For most people such an act would look impossible, but Percy was not most people, he was Perseus Jackson, a Demigod, the Son of Poseidon and the Hero of Olympus. For him this level of Hydrokinesis was as easy as breathing.

Keeping his eyes closed, Percy began to take slow, and deep breathes, focusing intently as he kept drawing on the moisture in the air. Eventually drawing more out of some of the nearby trees and out of the ground itself as he kept himself in a condensed cloak of water.

As he did this he could feel his latent Demigod abilities going to work, the water healing him of his aches and pains, clearing his head and giving him greater clarity. This was one of the good things about being a Son of Poseidon, all he needed was a bit of water and he could heal and reinvigorate himself.

With a final deep breath, Percy allowed his control over the water to drop, causing the cloak of water to collapse to the ground and soak into the forest floor. He didn't want to keep drawing on his power if he didn't need to, after all he was not sure whether this was hostile territory or not. It would be best to conserve energy until he had a better idea of just where in Hades he was and what in Tartarus happened.

Blinking his sea green eyes, Percy began to look around taking better stock of his surroundings. First thing he noted was that he was in a forest, a healthy verdant green forest that wouldn't look out of place in Maine. This for one made Percy suspicious, the last thing he remembered was leading the charge against Gaia, the Primordial Goddess of the Earth, and that had been in Southern Greece, a distinctly hot and arid country, and not a place which would have a forest like this in it. Which by process of elimination led Percy to thinking he was not in Greece anymore….

Frowning at this Percy then began to take stock of his current state. He was a little tired but had sustained no real injuries, or at least little more than a few cuts and bruises, all of which had now been healed. As for his equipment and entire, he was wearing a pair of brown leather boots, slightly worn looking black jeans, with Celestial Bonze plate armour strapped around his thighs and calves.

Around his torso he had a simple plain, red T-shirt, over the top of which he had a finely wrought Celestial Bronze cuirass, forged by the Cyclops' of Atlantis, engraved with the many feats he had achieved during his Demigod career. On both arms he had just as finely made Celestial Bronze gauntlets, both of had engravings of a trident on the forearms, a nod of respect to Percy's father Poseidon. The left gauntlet also had a clockwork watch face embedded into it, this was a useful addition, which not only told the time, but when twisted turned into a full sized, round Celestial Bronze shield, which like the gauntlets had the trident of Poseidon decorating it. Both of his shoulders were also protected by pauldrons which were attached to the cuirass, both of which were shaped to look like the heads of snarling Hellhounds.

At a first glance his equipment was all in good nick, apart from a few small battle scars they were all in almost immaculate condition. Which considering the length and ferocity of the battles Percy had taken part in during the fight against Gaia and her forces, was a testament to both his skill and the craftsmanship that went into forging his armour. Especially since those forces consisted of not just archaic monsters, but Gaia's children, the Giants and the Titans, some of the most dangerous, powerful and deadly beings that came of out Tartarus, the Eternal Pit.

Nodding his head that his armour was all still there and in good nick, Percy then check his weapons. First bring his hand to his right pocket, and feeling the pen within. At first glance this pen looked like just a fancy ballpoint pen, but if one were to take the lid off, then they would see the pen extend to become a four foot long, Celestial Bronze sword. Anaklumous, a blade that had almost become legendary since it had come into Percy's hands.

Smiling to himself, Percy pulled out Anaklumous and extended it to its true form. Just the feeling of the familiar blade in his hand was enough to fill Percy with confidence. The blade was perfect for him, it had the perfect length, weight and grip. It felt like an extension of his arm, and with this blade Percy had slain Titans, Giants and eldritch monsters than had long haunted the nightmares of mankind.

Glancing around his leafy surroundings once more, Percy began to take a few steps forward. His eyes narrowed as he kept his guard up, his blade held at the ready.

The last thing Percy remembered before waking up here was leading the armies of the Greek and Roman Demigods in a final charge against the forces of Gaia. They had charged the enemy forces in a wedge formation, with Percy acting as the tip. From there all he remembered was the clash of blades, the screams of monsters and men, the feeling of bringing death and destruction down upon the heads of his enemies. Then a final loud ear splitting shriek, as the earth began to shake and then nothing.

The next thing he remembered after that was waking up, alone, here, wherever here was. What happened after that… well he wouldn't know until he found some kind of civilization. After he did that, then maybe he could go about trying and get into contact with someone who might be able to help him or at least answer some of the questions he had.

Percy was soon knocked out of these thoughts as he heard a sudden beastly growl coming from some nearby bushes. Narrowing his eyes as he heard that, Percy shifted his stance. His decision made as he decided not to just run in head first and start killing. Instead he decided to adopt a more wary approach, the extended war against Gaia had taught him that much, drawing on his Demigod powers he began to extend his senses, using the moisture in the air to sense movement and vibrations.

Gripping his blade tighter, Percy lowered himself down into a fighting stance, as he sensed close to a dozen large creatures within a fifty feet of him, the extent of his senses. Even as he did that he could sense even more approaching, they were gathering almost like a back of wolves, or a swarm of monsters. The creatures were large, bigger than a full-grown man, and by the sounds of it heavier too. At first Percy thought they might be Hellhounds, but for some reason he dismissed that thought.

Soon enough his curiousity was assuaged as the sources of the growling began to approach, their snarls rising in volume as it prowled forwards. The dappled moon light that came through the overhead canopy soon revealed the source of the growls and snarls.

At a first glance, it looked similar to a Hellhound. But then a closer look revealed than this creature was far more anthropomorphic, with pale white bony spikes protruding from it, red markings, a white bone mask covering its face and red glowing eyes that held nothing but malice, hatred, and hunger.

Yeah, this beastie was similar to a Hellhound, but it was not one. Percy had killed enough of those monsters to know that much. This creature, it was something else.

Narrowing his eyes, Percy tensed as he heard the first beast howl before it pounced towards him. Its jaws open in a snarl and its claws ready to rend and tear Percy's flesh.

Percy didn't pause for a second as he took a single step forward, Anaklumous moving in a bronze blur as he brought it up and round in a single strike. The bronze blade bisecting the creature, causing the two halves of its now severed body to land on the forest floor behind Percy with a sickening crunch.

Glancing sideways, Percy couldn't help but blink in surprise as he saw the severed remains of the creature begin to disintegrate into wispy black vapour. The creature's remains disappearing was not what surprised Percy though, monsters often disintegrated after they were slain, their immortal souls being cast down into Tartarus where they would begin to slowly reform. What did surprise him though was that monsters when slain usually broke apart to become golden dust, they didn't turn into wispy black mist.

It was an inconsistency that made Percy uncomfortable, but for now he had bigger things to think about. As from within the woods he could hear twigs breaking and leaves rustling, followed by more howls and growls as the rest of this creature's pack charged in. Acting more like mindless beasts than intelligent monsters as they swarmed the lone Demigod.

Twirling his blade in his hand, Percy didn't waste a second as, when the next creature burst out of the undergrowth, he swung his blade and beheaded it. This was followed by a back handed swing which struck the skull of a third beast sending it crashing to the floor at Percy's feet. Stamping his boot down on the wounded creature, Percy swung his left hand round, creating a scythe like blade of water as he slashed a fourth creature in half, before he stabbed his blade through the downed beast at his feet, finishing it off.

Ignoring the disintegrating forms of the creatures, Percy instead once again took a ready stance as half a dozen more beast exploded out of the foliage.

Well…' Percy thought tiredly as he watched the beast charge him, their eyes burning red with and hate and their maws opened revealing teeth like small daggers. 'It looks like it's going to be one of those days?'

Hefting his sword Percy let out a battle cry before he threw himself forward, his blade already singing through the air, and a second sword, a blade made entirely out of highly condensed ice appeared in his other hand. As he struck down any creature that got in his way.

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(At Beacon Academy)

In a large oval shaped office an older looking man in his mid-forties took a sip from a cup of coffee as he looked over the list of students for the upcoming year at Beacon Academy. The man had unkempt grey hair, oval glasses and was dressed in a dark green suit. By the man's side was a black cane, with an intricate sliver handle.

This man was known as Professor Ozpin, the Headmaster of Beacon Academy, a school that was known for producing some of the best Hunters and Huntresses in Remnant. The man in question was currently musing over the applications he had received for Beacon Academy this year. Applications coming in from the training schools like Signal, and from those who had passed Beacon's grueling independent combat tests.

Earlier in the day he had been agonizing over how he had an uneven number of first years, which considering how those who were accepted were expected to find a partner and be part of a four person team, made things tricky. As this meant one of the teams would only be three person strong, which was unacceptable.

Now he had previously found a certain applicant whose transcripts to Beacon were patently false. A boy called Jaune Arc…, the boy came from a prestigious family known for producing skilled Hunters and Huntresses, despite that though the boy had not taken a combat test, nor had he been to any of the preparatory schools like Signal. Ozpin could have quite easily of cut him out, but then he would have needed to cut a further two students out. Which he didn't want to do as those two Hunters had proven themselves, ready and qualified for Beacon.

Luckily though due to events that happened earlier this evening, an attempted robbery of a Dust shop, a robbery that was stopped by a Signal student, who put her life on the line to do what she thought was right, he was no longer in such a predicament. With the young Miss Ruby Rose now invited to Beacon the numbers now made up to ten even teams of four. That being said though, he was still on the fence about allowing Mr Arc to continue on to Beacon as he had lied and cheated, however at the same time with his pedigree the boy could have the potential to become a decent Hunter. It was a difficult decision for Ozpin to make.

A knock rang on the door of his office soon drew his attention as he looked up in surprise, it wasn't often that he got unexpected visitors, especially so late at night.

"Come in." Ozpin called out, taking a sip of coffee as he put his paperwork down for now, and instead settling himself more comfortably in his chair his gaze fixed on the door.

Upon on his call, a tall blonde woman, with piercing green eyes and a statuesque stiffly entered the room. This was Glynda, Glynda Goodwitch, the Deputy Headmistress of Beacon and a long time friend and confidant of Ozpin's. It was because of their connection that he was able to notice the urgency with which she walked, and the serious expression on her usually strict and uncompromising face.

"Ah, Glynda, what seems to be the problem?" Ozpin asked easily, getting right down to the point as he knew just from a glance that she was in no mood for small talk or dillydallying.

"There is an issue in the Emerald Forest, the Grimm in the forest seem to be more riled up than normal. When I saw this I checked the camera network set up in the forest and well…." Glynda began as she strode across the room her scroll, a portable tablet like computer, in hand as she tapped a few interactive buttons. Causing a large screen on the side of the office's wall to light up, as it began transmitting the camera feed Glynda currently had running on her scroll.

Ozpin blinked in surprise at this action, carefully adjusting his glasses as he looked to see what had Glynda so serious. Upon looking Ozpin once again blinked in surprise, the cameras showed a young man who looked to be in his late teens. The youth was wearing some kind of bronze armour and was wielding a simple bronze sword.

Despite the simplicity of his weapon and the archaic nature of his armour though he was cutting a bloody swathe through a large pack of Beowolves. Even as Ozpin watched he saw the boy decapitate one Beowolf with a swing of his sword, before he shoulder charged another giving him enough time to sweep his sword around and bisect a third before lunging, his sword a golden blur as it impaled the second. Three Beowolves dead in less than five seconds, it was remarkable.

The boy's strikes were swift, accurate and economical, there was no wasted movement. Every strike was meant to kill or disable. Even as Ozpin watched the boy scythed through another five Beowolves, not stopping for a second as he continued on leaving behind a trail of close to fifty dead Beowloves to disintegrate.

Now Beowloves were not the strongest of Grimm, they were deadly to an untrained civilian, but to a Hunter, even a first year, they were easy prey to kill. That being said the boy was fighting an entire pack, something that could overwhelm even a fully trained Hunter, and yet he did not seem at all perturbed as he bulldozed through them.

Ozpin raised an eyebrow. The boy was clearly highly skilled, but judging by his age and the fact Ozpin didn't recognize him, it was a safe bet that he was not a qualified Hunter, which begged the question of what he was doing in the Emerald Forest alone and how he had gotten there in the first place. Looking closely Ozpin could see the boy looked uninjured, but despite that he could also see the boy was showing the beginnings of fatigue. His blows were still deadly and precise but they were beginning to slow, as with every Grimm he killed two more seemed to appear.

The fight looked to be turning into a battle of attrition, which against the hordes of Grimm, was not a fight any normal person could hope to win.

It was this was why Hunter's often fought in teams, as no matter how skilled a Hunter was they were still mortal, they still tired and they could still get overwhelmed by sheer numbers. Especially when bigger and more powerful Grimm got involved, which seemed to be the case here. Because even as Ozpin watched, he saw Ursai, bearlike Grimm beginning to appear form out of the forest.

Watching as the boy sliced of an Ursai's leg, before lashing out with his blade and ramming the four foot blade through the Ursai's skull. Ozpin decided he had seen enough.

"Glynda go pick the boy up. Get him out of there before he gets overwhelmed, and bring him here. Take a Bullhead." Ozpin said as he clasped his hands together in front of him, still focusing on the camera feed playing out in front of him as he did so.

Glynda nodded curtly at that, moving the moment she got Ozpin's permission and striding out of the office, her hands already in motion as she used her scroll to call for a Bullhead to be prepared for her use.

Watching the woman leave, Ozpin hummed to himself thoughtfully, before he looked back to the screen, the ongoing fight continuing to play out. Nodding his head, Ozpin then looked down at the roster for the upcoming first years at Beacon Academy a thought coming to mind.

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(With Percy in the Emerald Forest)

Percy let out a grunt of irritation as he cut through yet another one of the creatures. These things seemed to be never-ending, for every one he cut down another two seemed to take their place. More than that though it appeared as though tougher versions of these creatures were now appearing, no longer were just the wolf-like creatures attacking him. Instead there were now hulking bearlike creatures beginning to engage him.

The creatures were colossal masses of black fur and muscle, like the smaller ones, the bearlike creatures also had large bonelike masks and white spines sticking out of their backs. Also like the other ones when slain the creatures seemed to slowly break apart into black mist. Unlike the first creatures though, these ones were stronger, more durable and more ferocious.

Gripping the hilt of his blade tightly, Percy took a step back. His intense green eyes narrowing as he saw the creatures beginning to swarm him once again. They were coming from in front of him, behind him and from the sides, and if that were not bad enough he was still within the dense forest meaning that with night drawing in he as fighting in almost pitch darkness. The only light coming from the faint glow of his Celestial Bronze armour and weapons, and the few shafts of moonlight that managed to penetrate the forest's canopy.

Hearing the creatures growling around him, Percy once again drew on his Demigod powers, pushing away the mounting feelings of fatigue as he instead focused on surviving the night. Raising his foot Percy then proceeded to stamp on the ground, drawing on his Geokinetic power, courtesy of his father being the God of Earthquakes. The moment he did so the ground around him exploded, great spires of rock exploded from the earth around him, pointing out in every directions as they impaled the surrounding, swarming monsters.

All around Percy a palisade of stone spikes surrounded him, leaving a defensive buffer between him and the creatures, killing at least a dozen of them. Still though more of the appeared, climbing over their impaled and dying brethren, invading his defenses. Continuing their assault. The beast was inexorable, driven on by mindless hatred and insatiable hunger.

Taking a deep breath, Percy drew on his powers again before he stamped his foot down once more. The shockwave that followed blasted the spikes of rock out of the ground and sent them hurtling at the surrounding creatures. Watching the path of one of the stone spikes, Percy saw that it tore through four of the creature, before it struck one of the surrounding trees, ripping through the tree and causing it to fall.

All around him Percy could see the other trees beginning to fall, even as more than a dozen of the creatures died, either due to being impaled or from having the trees collapse on top of them. Percy had no time to think about that though, as he suddenly felt something hit him from behind, followed by the screeching sound of sharp claws being run along metal. Luckily his armour held.

Twisting around Percy's blade struck the creature attacking him in the juncture between the neck and the shoulder, the blade cutting a foot deep into the creature before he proceeded to boot it off the end of the blade.

Sweeping his blade around Percy drew the water out of the destroyed trees around him, cloaking both himself and his blade in a cloak of water as he did so. Narrowing his eyes, he extended the water around his sword to add an extra two feet of length. The instant Percy did this he felt invigorated, his fatigue temporarily pushed away as the proximity to water caused him to go through a sudden adrenaline high. Being Son of Poseidon was awesome sometimes.

Lashing out with his now extended sword blade, Percy began to cut through the masses of creatures, not even paying attention now as he haphazardly sliced and hacked at anything that got in his way. There were too many of them, the last time he had faced this many monsters by himself had been a year ago, in the depths of Tartarus, and back then he had nearly been overwhelmed and killed. In fact he would have died, had it not been for a friend he had made down there in the depths of hell, a friend who had dragged him out of the fray and taken him to safety.

He had learned from that mistake though, and here and now, he knew he was about to be overwhelmed. There were too many of the creatures, and even though he had destroyed a few of the trees, letting more moonlight in, the forest was still dark and he was still running on fumes. Lashing out with his sword Percy began to cut through the hoard, hoping to break away from the main group, giving him a chance to escape.

He had barely made it a few metres before was distracted by a loud, roaring sound. Looking up Percy saw a large vehicle, a kind he had never seen before appearing overhead, a large flood light attached to the bottom of the craft shining down upon him. From the looks of it his fighting had drawn the attention of some mortals.

Swinging his sword around once more, Percy decapitated one of the creatures, his other hand up in the air as he waved to get their attention. Due to the Mist, the magical veil that hid the divine form the mortals, he wasn't entirely sure what these mortals were seeing. But hopefully they would be able to tell he needed help.

The large craft shifted around as Percy watched it, still hacking and slashing at anything that got to close. It appeared they had seen him.

What then followed was the sound of gunfire. Percy blinked in surprise as what looked like two Gatling guns attached to the bottom of the vehicle, began to rain down heavy fire on the swarm of creatures.

At first Percy thought the act was futile, after all only divine metal could kill monsters. He was taken by surprise however as the mortals gun began to cut down the creatures. The ships guns aiming for around Percy as they drove the swarm of creatures away, leaving Percy free of attackers for the moment.

Turning in midair the aircraft soon showed it had bay doors in the side. Which upon opening revealed a tall blonde woman, who appeared to be holding a riding crop….

Percy blinked in surprise as he saw the woman's weapon of choice. Before pushing that to the side as he saw some of the creatures had gotten a bit more bold and were once more advancing on him.

Turning back to look up at the woman, Percy was once again surprised to see that as the waved the riding crop several purple beams shot forward. The beams of purple light struck the surrounding creatures, decimating at least a dozen of the ones closest to Percy.

"Quickly, get in!" The woman shouted at him, her voice barely audible above the sound of the vehicles engines as it hovered closer to the ground and the roaring sound of the Gatling guns as they continued to bombard the hoard of creatures.

Percy didn't need telling twice as he ran forwards, slashing out with his blade, cutting through the head of a nearby creature, before using its dying body as a spring board. Propelling himself up and into the vehicle, he didn't know who this woman was but, she might have some answers about what these monsters are. As after killing so many of them now, Percy was pretty damn sure they were not like the monsters he was used to killing.

Staggering forwards as he landed in the vehicle, Percy was only just aware of the woman calling out "Pilot, get us out of here." Her voice stern and uncompromising.

Pushing himself to his feet, Percy felt a sudden wave of exhaustion pass over him as he released his control on the water cloak, allowing it to spill onto the metallic floor of the vehicle. Staggering forwards Percy ignored the woman for now, trusting in his sense for danger, as he looked out of the still open doorway as the vehicle began to pull away, rising up and out of the forest.

Letting out a tired sigh, Percy looked up only to stop and stare as he saw the moon. Or at least what was left of it. Percy's could only look on in shock and horror as from where he was standing the moon looked like it had been shattered.

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AN: So what do you all think? Did you like it, is there anything I can improve upon? As I said this is my first story for this type of crossover, and although I love both the RWBY series and the Percy Jackson books I am willing to admit my knowledge of them is not flawless. Nor is my writing anywhere near that of a professional.

As for pairings, I have not decided on any yet, but I would be open to other peoples opinions if they can state a good reason behind it. Thanks.

Thanks a lot for reading!