Just a really quick, easy read I wrote up and typed today. This takes place in a sort of alternate universe (I guess?) from the canon, only because I don't actually know what actually happened to Cas, whether he is dead or alive, etc. etc. I just wrote this as if it were only his vessel that was destroyed.
It had been some time since his last visit to Earth. Seven months, three days, and eighteen minutes, to be exact. A lot of things had changed in his absence. He didn't need to have been there to feel it. The boys hadn't driven the Impala in weeks. The Leviathans were causing more damage by the minute, even as they hid away, dormant. Bobby was dead.
Castiel watched a familiar but distant scene escalate below him as he stood perched and stoic on the canopy of clouds concealing what was once his Father's kingdom. He felt uneasy, naked almost, without the form he had grown used to, his sturdy vessel. The two men he followed with his steady gaze paced the interior of another motel bedroom, clearly consumed by a debate or disagreement over something. Although the sight of them brought forth a warmth inside of him that Castiel had finally been able to identify as an unbreakable bond, he felt little joy. He was forced to reveal himself at last, and this would only cause more pain than happiness. Feathers rustled against his back, eager to take off and free him of this burden, but he remained locked in position; contained in a state somewhere between Heaven and Earth. The angel went through every possibility and every outcome in his celestial mind within a split-second, unable to settle on the best course of action. There seemed to be no definite path to making this easier for any of them. Before he had met those boys, the Winchesters, Castiel had never found making such decisions difficult.
In spite of his doubt, the angel's powerful wings unfurled to span across his back, reminding him of what he was: a soldier. He had conquered the apocalypse, proved fate a broken truth. What was this compared to fighting against his own brothers and sisters in Heaven? Castiel eyed his dark wings warily, those feathered things that felt so foreign, and gave them a resolving shake before slipping through the barrier of clouds and atmosphere. He descended, knowing at last where he belonged.
It was time to come home.