Cas doesn’t tell them what he’s done. A year goes by, and he doesn’t tell them. Neither does Jack, although the worried looks he shoots at Cas whenever he smiles or laughs are instantly sombering. Two years go by. Three years, and still the Shadow hasn’t showed itself again. After four years Cas has almost forgotten about it, all but secure by now in his own belief that he will never be as happy as the Shadow demands in order for it to collect on their deal.
Until Dean turns everything on its head, that is. Cas has missed the signs that this was coming – either that or maybe he subconsciously ignored them, because this can’t be happening. Not when it’s the last, missing piece of everything Cas has ever wanted. He’s been a part of a family for a long time now. He has a son. But this… He never thought he’d have this.
Dean’s lips on his own terrify him. Cas has died before – more than once – but he’s never felt fear like this. Because the thought of losing everything he has, of losing this now that he knows it’s something Dean is willing to give, is more painful than anything Cas can imagine.
But that just goes to show that his imagination is flawed, because Dean pulling away, mumbling a stuttered apology when he believes Cas’s inaction is a rejection, turns out to be even more painful. So Cas does the only thing he can to ease the pain, if only for the briefest of moments before he’s taken away: He cups Dean’s jaw and pulls him back in again.
Cas should tell Dean, he knows. He plans to. But every time he tries, Dean distracts him with a kiss or a smile or tender words that Cas has longed to hear him say, and he loses himself in Dean’s mind, Dean’s soul, Dean’s body.
The Shadow still doesn’t come, even as more years go by. It doesn’t come when Dean gets down on one knee in front of Cas, but the moment is tainted by Cas’s fear that this will be the moment he loses Dean forever. Or that their wedding day will be, but how does he say no to Dean’s request? He can’t. So he doesn’t.
Their wedding day arrives, and Dean is the happiest Cas has ever seen him. But it’s overshadowed by the constant fear hanging over Cas, and although he plays his shaking hands off as wedding jitters and the wetness in his eyes as tears of joy, he doesn’t quite realise they’re truly married until the next day. He missed his own wedding. He was there, he said his vows and he kissed Dean and danced with him at the reception, but… he missed it nonetheless. He’s still alive, however; that’s something, at least.
They buy a house, and Cas is afraid.
Dean smiles at him in a certain way when they’re cuddled up together on the couch, and Cas is afraid.
Each moment that he spends with Dean, he’s afraid will be the last.
Years go by, and Dean turns into an old man. And like all old men must do, he dies. He goes peacefully in his sleep, and although Cas will follow him into Heaven – Dean’s Heaven – he’s filled with a lifetime of sadness. For all the times he was afraid in Dean’s company instead of happy. For all the joy Dean felt in their moments together, but Cas didn’t.
And that’s when he realises it, moments before he senses that the Shadow is there in the room with him. The Shadow tricked him; tricked him into never gaining true happiness, even when he had everything he could ever want or hope for. Tricked him into never being able to enjoy the life he had with Dean. To never bask in the glow of the light that was Dean; to never take Dean’s love fully into his heart for fear of losing it all.
“Why?” he grits out, shaking. The Shadow’s only answer is a smile.
And then there’s Nothing.
