Dean couldn't see Castiel like this, watching him as the rain rolled off his skin. They stood a few feet from each other while the sky fell apart round them. The rainfall represented their own worlds in a way; realities that were unraveling and in pieces around their feet. Dean had lost his brother, or so he thought, and Castiel was fighting a civil war in Heaven. They were the same then, he and Dean. They were both shells of what they once were; a human and an angel so hollow and so... broken that neither one of them could breathe. Both following the same road to destinies that seemed so right, yet they were both doing it in all the wrong ways. That road ended here, right in front of each other, like it was always meant to be.
A peel of thunder crashed overheard and Dean jumped. Castiel could feel it. It was palpable on his skin, this raw emotion that he seemed to bleed through his pores. All the despair, the loss, the devastation that he felt were like words on paper; readable in the dark circles under his eyes and in the frown on his beautiful face. Dean was no less stunning in the rain. In this light, in this way, droplets of crystal magnified the freckles that Castiel could barely see any more, brought to his eyes detail that he would never ignore. The way his green eyes held so much depth, soul and kindness, the way his jaw tensed while he stood there thinking… Dean was, in a word, perfect. God's greatest gift.
When Dean sighed, so did Castiel. When Dean moved his head to look into the black horizon, Castiel mimicked the slight tilt of his head. And then… Castiel kissed him. Dean didn't feel it, wouldn't and never did. These were Castiel's stolen moments; seconds of intimacy he thought he'd never have with Dean. Seconds of peace and beauty that were so chaste and so… uplifting that God couldn't hope to create anything nearly as perfect. In that second, Castiel knew he would do anything for Dean, because of Dean, even make a deal with the King of Hell.
Castiel fought back a swell of emotion that pounded against his chest. Dean wouldn't feel the hand that brushed against his face, the thumb that crested over a cheekbone to wipe away what Castiel knew was a tear. Dean wouldn't feel any of it; not the pain of fighting another Apocalypse, not the sorrow that came with loss. Castiel would save him from ever hurting again.
Dean wouldn't hear Castiel whisper, "I miss you.," into his ear, wouldn't notice the sound of flapping wings as the angel took flight. The only thing Dean would hear was another growl of thunder and the rain's chorus against the rooftops.
Dean would never know how much Castiel truly loved him.