Loosely set after Episode 6.17. No spoilers though.

Fair Weather Friends

"Back off," Balthazar stared daggers at Dean.

"No," Dean was resolute. He couldn't let this happen. Not when he could stop it.

"This isn't your fight." The angel growled at him.

"Still doesn't make it right. You can't do this – you're angels for god's sake!"

"I will give you one chance," the angel paced within the burning circle. "Let me out of here now, or else I will bring down that wall in your brother's head… I will tear it down and relish the sound of his screams, even when you can't hear them anymore." Balthazar didn't even blink.

Dean froze. Rage threaded the blood in his veins.

"His soul is too damaged to be worth anything to anyone… except you," the angel mocked.

"You bastard," the hunter spat, his heart pounding so hard, his body shook.

"Maybe," Balthazar tipped his head to the side in thought. "But even your precious Castiel agrees with me on this. Why else do you think I've been sent to do the dirty work? He doesn't want to see that look directed at him."

"Bullshit." Dean refused to believe it.

"Believe what you want, I don't care, but let me out right now or spend the rest of your life wiping the crap off your brother's ass."

It struck Dean funny, that even after everything that had happened between him and Sam since Dean had come back from hell, there were still some things that hadn't changed. At all.

And this was one of them.

The moment Balthazar threatened Sam, he'd won –

And become the most hunted thing on Dean's 'to kill' list.

Castiel's friend or not.

"Fine." Dean growled as he stalked to the back of the room and picked up a fire extinguisher. He tossed it through the flames towards the angel. "But know this… This isn't finished. Not by a long shot."

Balthazar easily caught the extinguisher but didn't use it yet. "Of course not, Dean… It never is."

No matter what else could be said about the angel, he wasn't stupid, and waited until the roar of the Impala was a memory before smothering out the flames. Castiel was there when he finally got free.

"You couldn't have come any earlier?" Balthazar grumbled. "Rescued me or something?"

Cas stared in the direction Dean had driven, there was regret under the hardness on his face. "No," he stated flatly. "I could not."

His friendship with the Winchesters had been forged out of necessity, and he was afraid its destruction would be fashioned in the same way.

"Come Balthazar, we have a war to win."

The End