Castiel is tired.

There is no rest for the wicked, so the saying goes, and yet it seems that there is no rest for those God favored enough to resurrect, either. It has been war for two earth years now, and it seems there has been no rest since his garrison first descended into Hell to seek out and remove the soul of Dean Winchester.

Dean Winchester. Who treats him with more disrespect than ever. Who laughs in the face of the fight he can feel himself losing. Who thinks that Castiel is too angelic, as though that were a crime. There are many things to admire about humanity, Castiel will concede that. It was why he fell, after all.

But this is an angel's war, and needs an angel to lead it. There is not time for the slow doubt of humanity now.

Only decision, no matter how difficult.

And it is difficult.

He hopes Sam will understand that.

Dean is gone, for the moment; not far, but Castiel has seen to it that he will be – delayed. It should not take long, what he has come to do, for all that the impact will be large enough upon the two people he has called friends. For a moment, that thought almost halts him.

But Castiel has seen six of his allies die this week in fighting that has gained them nothing, and he cannot hesitate. Cannot doubt.

It is a cruel thing Dean did, in giving Sam back his soul, Castiel thinks. If only because it makes what he has to do that much more terrible.

He steels himself and crosses the parking lot to knock on the door. Inside he can sense Sam Winchester, relaxed, probably watching television. He adjusts his coat and raises a fist, knocks twice. It takes Sam a moment to open the door, and he blinks down at Castiel, seeming surprised.

"—hey, Cas." His eyebrows draw together in what Castiel recognizes as concern. "…you knocked."

"May I come in?" Castiel asks, not sure why he does when, after all, in five or ten minutes it won't matter. "I have some…business. To take care of."

"Yeah, sure," Sam says, and steps back. He still seems awkward, but not quite verging on hostile. That's good, on the one hand. It also makes Castiel want to turn away with something like guilt. "Dean should be back before long."

"It's you I wanted to ask," Castiel says, calmly. The room is small and cramped, and Castiel feels claustrophobic for a moment; or perhaps that is his own awareness of what could be betrayal (but is only strategy).

"Ask me what?" Sam says, looking more puzzled. Castiel thinks of Sam last year, willing to sacrifice himself to eternal torment to save the world. The thought eases his guilt, as he intended. Sam was willing to sacrifice then. What is to say he wouldn't be now?

He does not consider the fact that Sam doesn't know that he's going to sacrifice anything.

Castiel looks slowly around the room, and finally says, "About Purgatory," he says finally, not quite reluctant. "I have – reason to believe that Lucifer or Michael may – know something of it, and that it may be of strategic importance to the war."

He watches Sam flinch, and wonders a little at how even walled away, those names still have power. That somewhere, Sam's damaged soul still recognizes the names of its tormentors.

You are delaying, a small voice informs Castiel. Get it done with.

"I don't remember," Sam says, and halts, "You know – if I could, I'd help, but even if I did I couldn't tell you-"

"There," Castiel says almost gently, "You are wrong."

He can see Sam begin to understand, the way his eyes widen and he seems disbelieving. "Cas," he says, and Castiel takes a deep breath, reaches inward for his grace, and uses it to push Sam down onto the bed behind him, beginning to close the distance between them. "Cas," Sam says again, struggling against the hold he can't see. "What are you – no. No."

Sam's fear rips at the human heart he built over a year spent nearly human, but Castiel can't let it stop him. "If Raphael wins," he says, solemnly, "He may try to open the cage again. Start Armageddon again. He will shape a Heaven that hates humanity, a merciless, cruel facsimile of what it should be."

"You're not serious," Sam says, though he's fallen still. "Don't. Please don't. Dean-"

"Is not fighting this war," Castiel says, not sure who he's trying to persuade, Sam or himself. "I am. I do what I must, Sam. Understand that. I only do what I must."

He reaches out, pauses a moment as Sam tries to twist his head away. "I'm sorry," he says, and means it as much as he can, as much as he dares.

He rolls up his sleeve and plunges his hand into Sam's chest. Sam's whole body bends as he screams, and Castiel gropes deeper, seeking the skinned remnants of the soul he seeks. He finds it, and for a moment cradles it in a soothing net of grace, a sad, fragile, ruined thing. Last time, he was gentle, stayed away from the wall.

It is fragile, and in one thrust of power in the right place it crumbles.

Hell comes rushing out.

~.~

Castiel withdraws slowly from Sam's mind and soul, pushes them both down into sleep so deep it is almost something else. He feels the ache in his being, not in his vessel, the slow throb of pain that for a moment (centuries) he shared.

He lets out a slow breath and opens his eyes. Sam is limp on the bed, fallen back in a sprawl. His eyes are closed so he could be sleeping. There is still a pulse beating in his neck, after all.

But there is also blood smeared on his chin where he bit his tongue, and Castiel knows intimately the wreckage he left behind.

But he has what he needed.

No regrets, he tells himself. I do what I must to end the war. And it must end.

Sam would understand, he thinks, if he thought about it. If he were still capable of thought. It would, perhaps, be a mercy to kill him.

There are some things Castiel is still too human for.

"Forgive me," he says to the ruined man on the bed, and doesn't laugh at the irony of asking the boy with the demon blood to forgive an angel. If he lets himself think of it, it isn't demons who destroyed this man. Not really.

He stands slowly and stretches, trying to shake shared memories of Hell away. He moves for the door, needing to be gone before Dean gets back. Perhaps it is shame; or maybe just self-preservation. He wouldn't be surprised if Dean found a way to kill an angel with his bare hands, after this.

Better he never knows.

With one hand on the doorknob, Castiel glances back. It is a sad, sad irony, he thinks, that without his soul, Sam would have had a chance of getting through this.

He doesn't apologize again. Apologies are a human thing, and he cannot be human. Not if he wants to win this war.

And besides, it's not as though Sam can hear them now.

~.~

While planning for their next attack, he hears it.

Castiel!

He knows that voice, but never before has he heard quite that note in it, the note of fury and anguish and brittle despair consuming and degrading. He pauses, and lifts his head.

Castiel! Come on, I know you've got your war but – oh god, Sam, Sam's – dammit, help me! Help him!

The others are watching him. They can't hear Dean, and he wonders what they see.

Come on, Cas, if you never come again, listen to me now… Dean's voice cracks, breaks. He is screaming, truly screaming. He lets himself look, just for a moment, and there they are, Dean holding Sam's still comatose body close against his own.

Castiel turns away and pretends not to hear.

No regrets, he thinks. No doubts.

I did what I had to do.