Hello everybody. Been watching the show Supernatural and I wanted to have a crack at a crossover. So here it is, but there are some things you must know first.

1) The Greek pantheon is not weak in this story, the gods will be quite powerful. They won't be easily defeated by demons and angels and there is a reason for that which shall be revealed later in the story of course.

2) This is set before HOO series and near the beginning of season 5, therefore, no one has been to Tartarus. This is for a few reasons that contribute to the plot, one being that Tartarus will be similar to Hell in that time runs differently.

That is about it I believe. Enjoy.

Percy P.O.V

A blood curdling scream pierced the air and he awoke in a pool of sweat. His heart pounded in his chest as he remembered the nightmare that plagued him. He scowled himself for behaving this way, he couldn't get a decent night's sleep without the same nightmare coming to him, no matter how much he tried to push it away. It was at this point that he knew the inevitable conversation would take place, trying to convince him to give in.

'Well, I see that once again the nightmare has come. And I think it will continue to come every night until the day you die but that can be changed you know.' Said the voice in his head, the familiar deep and ancient voice that rumbled in his skull.

"Piss off, my answer remains the same." He growled, he grew tired of this, speaking to the voice in his head everyday but it couldn't be helped. The bastard wouldn't ever go away.

'Come now Percy, no need for that. I know we have had our differences but think of the endless possibilities! Deep down I know you want to say yes, you already took my gift. That shows you are willing!' The voice reasoned.

He glanced down at the Celestial Bronze watch on his hand, its alternate form being a pocket watch. He swapped the between forms, the wrist watch while sleeping and the pocket watch during the day, he rather liked the pocket form.

"Only because I needed another weapon to replace Riptide!" He argued but deep down, he knew that wasn't true, he took it for other reasons.

'You are lying to me. Now you know how I feel about that. Just as I know how you feel about the gift, me, the nightmare, everyone you have ever known... and the basement.'

"LEAVE ME ALONE!" He screamed and the voice remained silent. He was seething with anger because in the end, the voice had been right. He hated it with every fibre of his being, he hated it being right.

He had changed, he knew he wasn't the same Percy that was offered godhood, that was in love with Annabeth. No, he was different and there would be no changing that, never.

He got out of his sleeping bag and put on his new clothes that mirrored the new him. Extremely light and flexible plate armour that covered almost all of his body, made from steel like metal found in the darkest place of the Greek world.

He wore a red hood that also had a cape that flowed down to his back. It covered his shoulders and some of his arm. His gauntlets finger tips had claw like nails that made the ends of his fingers sharp points, a weapon of its own. The final piece and the most horrific was a mask, it had cracks along the sides that made it all the more intimidating.

Intricate patterns covered the eyes, a purple colour could be seen under the left eye while red was under the right. The middle was white where his nose was. The cheeks looked like they were being held together by stiches. The entire outfit gave off a demonic look (He looks like Jack of Blades from Fable).

He picked up his pocket watch and hung it from his leather belt. He put the mask on that was enchanted to remain on unless he personally took it off. He exited his tent and snapped his fingers, it shrunk and changed form into a wrist band, he picked it up with his sharp fingers and put it around his wrist.

He took off into a sprint, running at impressive speeds that the fittest athlete could never hope to match. He could have vapour travelled to his destination but he liked to run to clear his mind of the stress of having a voice speak to him every morning, not relenting in what it wants.

He refused to give in or think of saying yes until he had his revenge. His life was so screwed up but he was tracking down a demon, one that had ruined everything he ever held dear and put him in this situation.

Tracking lasted weeks but he had become a fearsome hunter, not relenting in the slightest for anything and had finally tracked its position to an abandoned warehouse near Chicago. It didn't take him long to arrive, he observed the building from a distance and noticed it looked empty, no sign of activity but he knew better, there would be at least half a dozen demons in there.

He took out his pocket watch swung it around on its chain as he approached and kicked a side door down, it smashed into pieces and went flying across the room.
He was surrounded by five demons already and their black eyes went wide as they took in the appearance of the stranger before them.

He radiated power in waves and the demons instinctively took a step back. He smirked but it was hidden behind the mask. Only his powerful sea green eyes could be seen giving a deadly glare at each demon in the room.

"Well, look who it is. I was wondering when I would see my favourite puppet again." A smooth and rich voice said from the shadows. A new demon walked towards him in the form of a young business man in his early thirties, Caucasian with light brown hair and blue eyes. He wore a three piece suit with a bowler hat to top it off. He had a devilish smile as he gazed upon the new intruder.

"Seth. I have come for revenge, and I shall take my sweet time taking it." Percy's demonic voice rumbled, that caused Seth's eyes to widen. One of the peaks of the voice in his head, he could change his voice to something more evil and dark should he choose.

"Tell me Percy, how does it feel to know that you were one of the Seals? The Seal of Innocence." He smirked.

"You lie!" He growled.

"Do I? I think we both know that I'm not lying, I have no reason to. Lucifer is free to walk this Earth with help from you. I must say, it was an intriguing experience being in your noggin, everyone calls you Seaweed Brain and yet you can be quite smart at times." He said smiling, his black eyes that had specks of gold in them flashed, knowing he had hit a sensitive spot.

"I'll kill you for that." He snarled. Seth just smirked and pulled out a dagger with ancient writing running along the blade.

"I would like to see you try Percy, you must know first that I am quite high up on the demon hierarchy. A warning that you will lose this fight."

Percy clicked a button on his pocket watch and it expanded into a sword that was similar to Riptide but with a few noticeable changes. The blade was made with a mixture of Silver, Iron and Celestial Bronze to cover all sorts of enemies, it had the same writing on it that Seth's dagger had.

The middle of the sword was transparent and in it you could see glowing sand floating inside the sword. A name was inscribed on the hilt, Vortex.

"Don't be so sure." His said demonically.

He raised his hand and the winds picked up to incredible speeds, launching the five demons around him in different directions. Seth too was launched and went flying into a wall across the wall. He stood up laughing and nodding approvingly.

"Oh this going to make for a good fight." He smiled but it soon vanished when a demon suck up on Percy. Seth raised his hand and the demon was shoved back.

"No one touches him except for me." He growled and the demons stood back watching warily. Seth smiled once more and readied himself for an attack.

Percy shot forth at lightning speed and swung Vortex, trying to cut the demon in half but Seth was faster than he thought. The demon jumped back to avoid the attack and slashed with his dagger, the attack was blocked and their blades locked.

The demon and demigod pushed as hard as they could, trying to gain the upper hand. Percy grabbed the demon's wrist with his free hand and ice started to form and travel up his arm. Seth growled in pain and kicked him in the chest, he smashed into a pile of crates.

The demon clutched his arm and glared at the armoured demigod before him. his entire left arm fell off from frostbite, Seth roared him pain.

"You'll pay for that." He said through gritted teeth. Seth raised his remaining arm and an invisible force pushed him back and held him against a wall.

The demon approached until he was face to face. He brought his mouth right next to his ear.

"Tell me, demigod," He spat. "How did it feel?"

"Shut up." Percy growled, anger growing in his chest as unwanted memories started to return.

"To see the terror on her face as you cut into her flesh with the knife." Seth smiled.

"I said shut up!" He snarled, the air growing humid and the skies turning dark.

'Yes Percy, that's it, focus on the anger and hate. Use it as a weapon and show this low life your wrath, he ruined your life, he made her suffer and forced you to watch. Unleash your fury.' The voice whispered, speaking up and only adding more fuel to the fire in him.

"I bet you enjoyed it, I know I did. And after we cut off her fingers and toes, didn't we have fun? Humiliating her and shattering her dignity, taking her for ourselves, I bet you loved every second. Want to know the best part? She died thinking you were a monster, she thought it was you all along." Seth taunted.

"ENOUGH!" He roared, the skies had darkened and the winds blew at unbelievable speeds, the warehouse shaking to its core. The ground rumbled and cracked as the earth shook from his raw fury. Lightning struck all over the ground, deafening blasts of thunder followed.

The demons that had been watching were struck by lightning and exploded in a shower of blood. His sea green eyes glowed brightly with untold power and fury, the force that held him felt like nothing as he broke free and grabbed Seth by the throat who was just smiling at the destruction being caused. The warehouse was falling apart around them as the earthquake grew stronger and stronger.

"I have and always will break you. Nothing gives me any greater pleasure than to witness you crumble before me. As much as I would love to finish this little spat with you, I have things to do and people to kill." Seth smirked and black smoke flew out of the vessel. The smoke flew away, Seth had escaped.

'He is gone Percy, calm down, he is gone.' The voice said soothingly, the winds died down and the skies cleared and got brighter. The earthquake subsided and his eyes stopped glowing. He threw away the dead vessel he held and yelled in frustration.

"He got away… I'll kill that son of a bitch if it's the last thing I do!" He growled and clenched his fists.

'That low life scum will die, we'll make sure of it. But there is nothing you can do about it now. So demigod, what will you do now?'

He knew what he would do, the demon was gone so he had only one other thing he could do.

"I'm going to Camp Half-Blood."

Dean P.O.V

The deaths of Jo and Ellen had struck them hard and it was all for nothing, they didn't kill Lucifer and he raised Death. He and Sam were field stripping their guns in a crappy motel room in silence.

"Sam, Dean." A voice said behind them, he jumped slightly and saw Sam do the same. A man with slightly spiked hair stood there in a trench coat and stared at both of them blankly.

"Dammit Cas, scared the hell out of us." He said.

"We need to move, now." Castiel said.

"Why? What's going on Cas?"

"Land near Chicago has been decimated with storms, high speed winds and earthquakes."

Sam looked worried for a moment. "Lucifer?"

The angel shook his head, "No but I felt it and I'm sure others did too, it was something powerful and old."

"Well that narrows down our search doesn't it." Dean said sarcastically.

"Yes, it does." Castiel said and he rolled his eyes.

"Cas, I wasn't being serious. Everything we are dealing with is old and powerful, you are going to need to tell us a little bit more than 'powerful and old'." He said and the angel nodded and frowned.

"I'm afraid I don't know any more than that except that it was involved with the breaking of one of the seals. I have found a way to track it and it is heading to New York at an incredible pace, we must leave at once."

Dean just gave the angel a 'you're joking' look, he noticed his brother doing the same.

He knew Sam was thinking the same thing as him, why on Earth would they want to go after an ancient and powerful being that broke one of the seals, it would most likely kill them. A stupid idea.

'Although, we are going up against the Devil and Michael… That is probably the stupidest thing we could do.' He reasoned to himself.

"Alright, to New York it is. Let's go hunt us a… well whatever it is." He said unenthusiastically and grabbed the keys to his Impala.

There we go, I made Percy look like Jack of Blades because I simply like the way he looks. Everything involving Seth and the voice will be explained soon enough.
See ya at the next chapter!