Title: Promises and Penance
Spoilers: mild spoiler for Season 8 Episode 8
Disclaimer: I do not own the rights to Supernatural.
Warnings: references to suicide

Dean doesn't tell Sam what Castiel had told him – partly because it isn't his place to tell him, but also because if he does it will make it real. And Dean isn't able to accept that Castiel could be so… human. So the first chance he gets to talk to Cas on his on, he takes.

"Cas? Promise me something."

"What?"

"Promise me."

"I can't promise anything, until you tell me what it is."

Dean's hand reaches out and grabs Castiel's wrist tightly. "Don't ever kill yourself."

Castiel's brow furrows, and a pained expression haunts his face as he cocks his head to the side and looks, really looks at Dean. His eyes narrow as they take in the desperation and the pain and the fear that he hides from everyone, but can never hide from the angel who raised him out of Hell.

"I've lost you too many times already, Cas – please don't make me lose you again."

"I don't think I'm strong enough to live with everything I've done, Dean," he says quietly, and it is almost an apology.

Dean's hand, which hasn't moved from Castiel's wrist, grips him tighter. "You're stronger than me, Cas."

And if you're not strong enough, then what chance have I got? Castiel hears Dean's unspoken words.

"Dean…"

"Cas," Dean tries, "you said that you chose to stay in Purgatory because you needed to do penance. But you're not there any more – you're here. Now that doesn't mean you can't still make up for it, but if you kill yourself then you never will."

"So my guilt is a part of my punishment," he says slowly, beginning to understand where Dean is coming from.

"Yeah," Dean agrees, glad he's starting to get through to his angel. But he's not prepared for what Castiel says next.

"But then what are you punishing yourself for?"