Percy Winchester?

Disclaimer I dont own either PJO or Supernatural so dont expect another one!!! 

For Percy Jackson a boy from an Ancient religion, life was great, and all was well in his family. The Gods were leaving him alone, there were no more manic older races for a 17 year old to fight. Apart from the constant nightmares and feelings of inadequacy, apart from the two wars he has participated in, in the last several years.

But those issues were being worked out, he was getting councilling at camp half blood, and the nightmares were being treated by several gods, who all felt they had a debt to him, again. Apart from these few things Percy felt life was good. He had a Girlfriend, named Annabeth who he loved, he had a baby sister her name was Estelle and he doted on her. He also found out about two new brothers, half to be exact, not on his fathers side mind you. They were a big deal for him because they were from his mothers side.  

Eventually his life started to spiral, and things just got worse and worse and worse, it all started with flower. For their anniversary he gave Annabeth a rose, a red one, like the one from the myth of Aphrodite and Adonis, she got so exited that she gripped the rose and gave herself a cut. After a few days the cut wasn't healing properly and Annabeth went to get a blood test, because even though she knew it wasn't gangrene she could not convince Percy otherwise. The result they got back was worse than either of them could realise.

And that was the exact moment when he know the Fates hated him. Annabeth was diagnosed with terminal Cancer and was given months to live. The results of the blood test were conclusive, she was going to die. This was only that start of the problems. 

 Apparently Tartarus, (or hell depending on who you ask) was slightly radioactive, and so with Annabeth spending a significant amount of time there led to without imediate treatment led to the tumours starting to grow, and she brushed off the pain as training pains. Why doesn't Percy have Cancer, why didn't he have radiation poisoning? Well when Damsen the only nice Giant healed him, he took away the ionizing cells in his body, and gave him a slight immunity to the effects of Tartarus. So now Percy is left with no soul mate, and was left with worse news left to come. 

His life started to spiral even faster when, before he told his "mother" about Annabeth, Sally explained he was not infact her son. But the son of a dead woman who was brought back from the dead as a surrogate mother for the sole purpose of having the hero of Olympus. She explained that he did have some family. Two brothers who could be the reason the world ends. The Winchesters.

He had heard of them before. Mainly from the Hunters of Artemis complaining that they are doing there job, and that they don't need some wanna be Hunters getting there kills before them. But they haven't been shot down by any moon arrows yet, due to there apparent importance. Not in the Greek world, in the Christian world, because apparently 3 pantheons were not enough, now angels are real as well, as well as every other: Story, religion and pantheon, that anyone had believed in.

Percy was not surprised, he had been told many times that every story is grounded in truth. So sure why not the Bible, Quran or any other religious text. He was kinda pissed off that he might have a small part to play in the end of the world in the way he knows it. He was especially pissed because, he had saved it too many times for it to be destroyed because two brothers are having a tiff. Also he lived in that world and he liked it the way it is thank you.

Then he was told, by some random Angel who's name he dubbed, Zechariah the holiest douche to ever ruin my life, or Z the runnier for short. Z claimed that if he didn't help those men, Z who was apparently very high up in heaven, would not let Annabeth in and she would go mad as a ghost or her soul would be claimed by a vengeful Tartarus.