A/N: After watching the first couple of episodes with the new season, I've stumbled on the idea of the Winchester boys maybe having to battle. So I decided to expand on the idea growing in my head. What if they really had to face each other? The world could end and if it does, whose expense would be at? Or if it could in fact be saved, whose blood would be shed in the process? I'll be bringing in some other characters we've seen in the past on Supernatural and maybe tying in what's going on with the show but I am branching out on my own, don't expect everything to be the same. So yes, there are spoilers for season four in this.

"I know you can do this Dean," Castiel says although Dean is torn entirely.

Save the world, or dare he even think it, kill Sammy--his Sammy. Wait, wait a second. Dean was jumping to conclusions like he always did. There'd have to be a way to save him and he sure as he was willing to find it, with or without the help of a freak with wings.

He breathed out a sigh of frustration. "He's my brother. I don't know if any of you understand that upstairs but he's my brother, my blood, and I can't just shoot him in cold blood like your God would do like he has done with millions of people already.

Castiel knew this wouldn't play out nicely, he was having a difficult time getting Dean Winchester to trust him or at least in God. One thing at a time but that was something they didn't have. Their visits were short and eventually Sam Winchester would have to find out just what he was up to. Question was: could Dean in fact trust his own brother enough to tell him?

Soon he'd have to leave again but Castiel had to get through to him. He brought him out for a fight and Dean needed to be on their side. "Look around, bodies are piling up everywhere. You're on the good side, it's your brother...Your brother isn't." Castiel shook his head, "You were gone for months, who's to say that the demon blood coursing through him hasn't consumed more than you thought?"

Dean smacked the wall, furious. "He's my brother!"

Sammy played with cars at five, was top in his class throughout all his years in school, college boy even. He was innocent, after everything that happened he'd have to be. Ruby had tried to mold him into some kind of soldier and Dean did everything he could do to prevent it from happening. Which was why when he learned that Lilith had taken her "far away", he was relieved. She was gone, so he thought.

"He's my brother," Dean said again, quieter. "I know him, you know him on paper." He scratched the back of his head trying to come up with something. Sam was supposed to take on the thinking, not him, not with things like this. "I have to tell him, about this weird enlightenment thing." This had to start somewhere and Dean was finding it more and more troublesome keeping it from his brother rather than getting his help.

"You can't," Castiel demanded and Dean looked back in surprise. "This job was given to you, not you and Sam. There's no trusting him and we can't afford to take any chances here. There's too much to lose." The look in Dean's eyes said otherwise, he was going to tell Sam whether Castiel liked it or not. "This apocalypse isn't just a demon crusade resolved with a few spells, people are going to die and Sam isn't supposed to be on our side."

As awful as it sounded, Dean wasn't fazed. "Yeah yeah because he was chosen to lead some kind of demonic army. Blah, blah, blah, I've heard all before but Sam isn't one of them. He hasn't raised some kind of army of darkness and I don't see him doing it anytime soon. I'm the one that went to hell, there's not a chance that a place like that will ever see the likes of Sam Winchester."

"Maybe some day you can thank me for taking away those memories of hell," Castiel said coolly. "Time changes everyone, angels aren't excluded in that category and most aren't as understanding as I am."

Holding his stance steady, Dean looked around for any lurking shadows, none were in view. He glared at Castiel, testing this angel and seeing that there wasn't a lie in his eyes. "Well you can tell them to come, bring a whole flock if you'd like. I've fought demons, ghosts, vampires, werewolves, you name it. A few giant birds aren't going to make a difference. Sam's off limits."

That was disappointing and not something Dean could do. Castiel knew that he was either with them or with Sam. Both was not an option but Castiel figured if he had enough patience, Dean would come around. He'd have to make a choice and very soon, others were starting to talk. Dean Winchester this, Dean Winchester that. He was a waste of time...but it was God's will. Angels weren't as sympathetic.

"Soon you won't have a choice and a side will be decided for you. You won't want that." Castiel could imagine the suffering he'd endure because of his devotion to his brother. "There's not a way around this, decide Dean, and soon."

It was almost as though Dean had imagined Castiel who had disappeared entirely. It was late, he'd sneak back inside Bobby's house to fall back into his slumber but instead of crashing instantly, his mind kept him awake. This was too big to keep from Bobby and Sam. Others could help and right now he could use it. Finally a yawn submerged, his body was growing tired at last. His last thoughts decided just what he'd do. Screw Castiel and his angel friends. He was going to let Sammy know everything.

Castiel returned to an empty warehouse where angels had gathered to hide away and discuss matters that needed to be taken care of. He sighed knowing he'd have to be the bearer of more bad news. "Dean Winchester," some perked up while others were noticeably disgusted by the very mention of his name. "He's willing to help but he needs a little faith."

"He needs faith which would take time," Uriel spoke up. His lack of compassion for the human race hadn't gone unnoticed and he was not the only one that felt the same way. The difference between the other angels and Uriel not only disliked the human race but that disliking extended towards the Winchesters in particular. "You waste your energy on him when he shares the same bloodline as Sam. He should not be entrusted with this, with us."

"He commands it," Castiel reminded him. Uriel turned away in disgust, mumbling. Others were skeptical, some felt the same. "No one has the right to assume that Dean is his own brother. No one can assume that Sam has already turned over to the other side."

Uriel stepped in front of the others where Castiel stood. "No one can assume that he hasn't! You've seen what he can do Castiel, there's no denying the power there. Look at the innocence he's spilt."

"What he could do may in fact help us if he was on our side and the side he resides on is unknown. He doesn't know how to harness his abilities," Castiel defended the Winchesters, someone had to. Why would God choose Dean Winchester if there wasn't any redeeming qualities? "Dean Winchester has proven himself worthy..."

Uriel crossed his arms, "Oh? Has he now? Those ghosts Lilith put out seemed to think otherwise. Death is caused by these two Winchesters everywhere they go. Do you honestly think Sam could be on our side? His blood is tainted and you act as though Dean is our savior while Sam is made out to be theirs when Dean doesn't believe. He is no savior."

That had been taken into account actually. Castiel was no fool. Everything had its purpose and this certainly did too. "He may very well be."

A/N: Dean versus Sam? Holy hell, hah. I find it a bit odd that Sam's the one who believes in God, yet Dean's the one with an angel. Anyways, I've only written a one-shot or two for Supernatural, never a full blown fic like this. So feedback would be very appreciated.