He is used by now to dreaming of Cas.
It might be in the form of a nightmare, watching over and over again as Cas left him behind, headed to that place where he couldn't follow. Or it might be, in rare, blissful until he wakes up, occasions, just a dream of Cas being around, waiting for him at the kitchen table, back to the door, a coffee pot already waiting for Dean.
And maybe because he is so used to such visions he can tell something is different this time around.
First of all, Castiel, because he knows it's Cas anyway, doesn't look like his usual self. Dean has to crane back his head to be able to see him. Tall as a building, massive wings, three pairs of them, a warm blue glow that reminds Dean of being healed, of his pain being taken away. He can see that, as normal as the rest of his body seems to be, he has three heads, a central one, resembling a humanoid mask, one on each side, a bird he doesn't recognize, a deer.
He doesn't doubt, not even for a second, that this is Cas he is standing in front of, he would recognize him anywhere, his soul would at least, like it is looking at the very being that once cradle it out of Hell.
A voice resonates inside his head, it's Castiel, but at the same time it's something unfamiliar, old and sacred.
Dean is sure, in a delirious sort of way, that this is real.
Dean huffs at that, prays he won't wake up, not yet, not ever.
"You told me once humans tend to complicate things, I bet I'll get it."
I'm back, back in Heaven, I mean.
Dean wants to ask for how long has he been back, he wants to smack Cas for not coming around to see him sooner.
They need my help, I ought to make things right.
"You are punishing yourself, that's what you are doing."
Castiel ignores Dean's comment.
A pause, as massive as Castiel himself.
It was selfish on my part to come here, I should have left you alone.
"You came here for a reason, spit it out."
You wanted a life away from all you once ever knew, I am just a reminder of all that pain and blood, Dean.
Dean shakes his head. "Oh fuck off, Cas."
A small, humourless laugh is all the response he gets.
A big sigh echoes inside his head then,
I wanted to see you one last time, let you know I was okay, because I was up there, forcing myself to believe you wouldn't want to know I was back, that you would be angry, that you would refuse to see my face again, and I would have understood that, of course. But part of me knew it was unfair to make you suffer thinking I was gone, forever.
Dean had never lost his hope before when it came to Cas coming back, his faith, but... This time around, he was sure it was over, really over, and he wasn't taking it that well. He is a mess, that's what he is.
"You could have come in person, no need to appear like this, in a dream," Cas was just, scared, and Dean gets it, even if he hadn't been the one that had expose all there was to see to the light, his best kept secret out in the open, "I'm not mad at you, even if you keep dying on me, fuck Cas, I am mad we didn't talk about it sooner, that we were just a couple of stubborn dumbasses."
The laugh he gets now is louder, real and full of warmth.
"I am just happy you are back."
No need for him to finish, Dean knows what he means,
" I want to be face to face when I tell you."
Dean wakes up, he notices then the tears trailing down his cheeks, he wipes at them, knowing they are tears of joy, he also notices what woke him up, an insistent knock on his door. He is out of the bed in a blink, rushing to open the door.