Let’s talk about Cas driving back to the bunker, after Sam calls to tell him that Dean is (sorta) alive, and he doesn’t think about it, doesn’t think about it and doesn’t think about it, still shaky with grief, bone-deep and exhausting, different than the slow, sullen sadness he’d felt when Dean had told him he couldn’t stay, a constant pain that slices between ribs like a knife, crawls up into the back of his throat. And when he finally sees Dean, upright and (not quite) breathing, blood smeared along the side of his jaw, he feels relieved and devastated at exactly the same time, his near-humanity making everything worse, his emotions amplified by the remainder of his grace until they are too big and too loud and too bright, itching underneath his skin, flickering in the corner of his eye.
He can smell the sulfur shrouding Dean’s blood, taste it on the back of his tongue, thin and sharp, a taint in the air, and he can (almost) see what’s left of Dean’s soul, the righteous light that had guided him through the gates of hell, into the deepest and darkest corners of perdition. His chest aches as he looks at Dean’s new face, Dean’s demon face — the ragged, tapered curl of horns, the longer, sharper teeth, the way the eyes inside the smoke are (nearly) the same impossible green of his vessel — but he neither repulsed or afraid, his instinct to protect Dean stronger than his impulse to smite one of hell’s creatures. He reaches out, wanting to pull Dean close, wishing Dean would allow it.
"Cas," Dean says, rough, the blood on his face twisting the lines of his mouth as it moves. "You — um." He cocks his head to the side, his eyes burning black, and Cas realizes that Dean can (finally) see the truth of him — all six of his wings; all four of his faces, three of them formed after animals long since extinct; the holy light pulsing at the center of him, weakened now, dim in more places than not, the rest of it fading, tarnished a cloudy, sickly yellow. He waits in silence, expecting Dean to be horrified, fearful, but Dean just shakes his head, murmurs, "huh," under his breath.
"Nothing. I just — I expected the you you to be bigger, is all.”
Cas smiles a little; he remembers the day Dean summoned him to that barn, how he’d given Dean an estimate of his true size and Dean had crudely accused him of boasting. Still wanting to touch, he slides his hand up to Dean’s shoulder, lets it rest at the curve of Dean’s neck. Dean’s eyes burn black again; he makes a low, choked noise in the back of his throat, curling his hands into fists and Cas pulls him close.
"I fucked it up," Dean says, his face hidden against the side of Cas’ jaw. His sulfur-smell is stronger this close, but Cas breathes it in deeply, determined not to flinch. "I fucked it all up. I lied to Sammy, and I got Kevin killed, and I couldn’t kill Metatron, and now — now I’m — "
Cas kisses him, tastes dust and smoke and ash, but it’s just there on the surface, hasn’t yet burrowed into Dean’s soul, and that fills Cas with something new, something lighter and brighter than the grief he carried on the long drive back to Kansas, and when Dean hums against his mouth, curls a hand into his hair, Cas recognizes this buoyant, brimful feeling for what it is: hope.
