The Jabberwock. Castiel only recognizes the name because he familiarized himself with Lewis Carroll's work soon after he got here. A raging monster. The jaws that bite, the claws that catch, or so the poem had said.

Of all the things to take him out for good...

Then again, Castiel had always imagined he'd fall in battle. In fact, for a time that's exactly what he had been looking for. During Purgatory, and even afterward, a part of him has been searching for a way to martyr himself, to make up for all of his sins in some sacrificial act.

He's learned better since then. He's realized that he's of more use alive than dead, and he's seen the pain in Dean's face every single time he leaves and then comes back. It's hanging on Dean's face right now, like a shroud, worse than ever.

Once again, Dean's saying it without saying it, that he died. Castiel almost feels like apologizing for something that hasn't even happened yet. He doesn't actually say the words, but he meets Dean's gaze and it wavers there, in his eyes. I hurt you again. I can't seem to stop doing that.

"That must be why you're here. To make sure that it never happens."

He lifts his arm up, reaches a hand out to set carefully on Dean's shoulder. "Dean, you need to tell me everything."