Of course Castiel knows it’s probably a bad idea from the start; of course he knows whatever they might share will only end in pain.
Neither of them talks about it, though, because he knows they both avoid thinking about it.
Castiel has loved humanity since the moment of his creation; it is a duty and one he’s always had very few qualms about following. It’s different with Dean, though. It is consuming and bordering on dangerous. It pulsates through him, chaos and beauty and cold. It’s difficult to describe because Dean is the only human—the only of any being—that Castiel has ever felt this way about.
The problem with humans—well, there are many problems with humans, he’s come to realise. And most of them are unavoidable or, at the very least, unsurprising. So Castiel knows, objectively speaking, that Dean will get older even though his own vessel will not.
It doesn’t matter much at first because Jimmy was older than Dean, and even when Dean’s age passes that of Jimmy’s body, it’s hardly noticeable. But humans are frail and transient; they will always wither and die.
Castiel knows this, but he can’t bring himself to be rid of Dean.
He’s about to knock on the door of Sam’s apartment—Dean is staying with him for the weekend and in their years together has forcefully asserted the importance of knocking—but stops himself when he hears the brothers talking.
“Look, Dean,” Sam is saying, “of course I’m happy for you—”—Castiel can imagine Dean’s eye roll at that—“but you know this is gonna end bad, right? I just—” Sam breaks off, probably to give Dean his perpetual I’m worried about you even though you’re thick and a bit of a dickhead frown; the one Dean fondly refers to as the little brother who thinks he’s the big brother bitchface—or Bitchface #36.
“I’m not fifteen, Sam,” Dean counters, defensive and irritated. Castiel curses himself for his poor timing. Even if he weren’t listening outside the door, he doubts either would be in the mood for his company, even though they invited him. Of course, it would be convenient if they could go more than an hour without arguing about something but Castiel is certain there’s a better chance of Lucifer confessing his love for humanity.
He does want to hear what Dean was going to say, but he decides it’s probably better to quell the argument with his awkward timing and even more awkward social interactions (it’s not his fault humans are so confounding; personally he’s a fan of saying directly what one means, but humans rarely do this) than to let it fester.
When he knocks, Dean opens the door and his smile becomes a little less tense when he sees Castiel. “Man, we don’t even need to call you; you just always show up when we’re thinking about you. It’s actually kinda creepy,” he adds after a moment, but the twitch of his lips lets Castiel know he’s kidding.
He lets that last part go and, as he enters the apartment, arches an eyebrow, asking, “You were thinking about me?” It would sound coy coming from anyone else, but even Castiel’s distinct lack of charm can fluster Dean.
True to form, Dean scowls. “Shut up, Columbo,” he says instead, and Castiel laughs despite himself. (He never could bring himself to get rid of that trench coat, in spite of Dean’s best efforts of persuasion).
The reason Dean is here is that it’s his fortieth birthday and even though Dean claims not to care, Sam had insisted. Dean has said that Sam’s mostly apple pie lifestyle has turned him into “a soccer mom on acid,” so there’s really no way to avoid it. Castiel is pretty sure Dean is secretly pleased, though.
Still, Dean’s birthday is a bittersweet sentiment for Castiel. He keeps getting older and older and Castiel stays the same and sooner than he knows it, the difference will be blatant and the distance it causes might all but kill him. But he shows up anyway and celebrates and eats cake and kisses the frosting out of Dean’s mouth while Sam and his girlfriend make gagging noises at them.
Later on, Dean surprises him with an uncharacteristically pensive post-coital mood.
“This is gonna get weird, isn’t it?” he says finally.
Castiel turns to face him. “In what way?”
Dean doesn’t answer right away, but he won’t look at Castiel when he does. He’s staring up at the ceiling, hands clasped behind his head in an attempt to appear as speaking casually. “I always thought—well, I thought living to be forty was just a pipe dream, y’know? Something or other is always trying to kill me. But—if you stay, and I just keep getting older, is that weird? Does that make you a pervert? I mean, you’re already thousands of years old. There isn’t a handbook for this shit,” he grouses.
“Sam says this will only end in disaster for us,” he adds after a moment, all traces of humour fading into solemnity.
Castiel wants to say, No of course it’s not weird; everything will be fine, Dean. But he’s not Dean’s mother and everything won’t be all right and there’s a lot of pain ahead for them—and he’s not certain any of the good parts can stifle the misery in store. “He’s right,” Castiel says, and closes his eyes because he can’t close his heart.
“Yeah,” Dean agrees gruffly.
It’s probably not an ideal birthday celebration.
Castiel spends a lot of time tracing the lines on Dean’s face—with his fingertips, with his lips, with the fuzzy edge of awareness at the back of his mind.
Dean always leans into the touch, cupping the back of Castiel’s neck in his hand, murmuring things Castiel doesn’t think Dean is even aware he’s saying. Dean is ever-aging, but always beautiful. Something about him—his soul, his unwillingness to bend to the will of others—transcends his physical appearance, although Castiel has never understood the idea that aging takes away physical beauty.
Sometimes, Dean will return the movements, skimming his fingers over Castiel’s skin. It makes his Grace cling tightly just under his skin and his cheeks flush. And Dean will kiss his mouth and neither of them will say it’s getting harder to ignore.
Sam looks at them sometimes and sighs sadly, but he’s given up on trying to talk them out of it. Well, it’s not much he’s ever wanted Castiel to leave or for the relationship between him and Dean to revert back to what it once was—pining awash with misunderstandings and miscalculations. But he’s found a nice girl, Priyanka her name is, and they’ve settled and “maybe someday he’ll grow a pair and pop the question” Dean says, and Castiel knows it must hurt him to realise his brother will never have the same thing.
It pains Castiel too; there’re so many things he is for Dean, but sometimes it feels like there are infinitely more that he can’t be. He could Fall—in the big way, “pull an Anna,” as it were, but he won’t. And he knows Dean wouldn’t ask him to, probably wouldn’t even want him to. He hasn’t visited Heaven in years, and doesn’t really plan on going back (though from what he hears it’s become quite bureaucratic) but being an angel is a part of him, just as being a hunter is part of Dean.
Sometimes it’s still hard to believe they’ve ended up together—in about every way Castiel can think of. Not because their feelings were ever particularly unnoticed or unexpected, but because they spent years dancing around it all, pretending it never existed. A bit like the way they pretend age doesn’t matter, doesn’t affect them. That’s fitting enough.
Still, even as he moves above Dean, mouths the salt off his neck, part of him thinks maybe age doesn’t matter—or doesn’t always matter. He loves Dean and that doesn’t change even as Dean’s age does. It doesn’t go away, but it’s not always at the forefront of his mind. And someday Dean won’t have any age at all, but that’s something Castiel really does keep locked up under layers of cobwebs and sand and ash.
When all is said and done (and when Dean is gone) Castiel is certain he still wouldn’t have wanted to go without what he has now.
“I’m old enough to be your father,” Dean complains one day, deceptively light.
“I’m several millennia old.”
Dean rolls his eyes and sighs with false exasperation. “Yeah, but Jimmy is what? Thirty-five? That makes me almost twenty years older. This is messed up.” He’s looking in a mirror, examining the grey hairs scattered across his scalp.
Castiel is actually quite partial to them; they’re charismatic and distinctive, just like the freckles that still dot his face. He doesn’t say any of this, though. It always makes Dean uncomfortable and Castiel knows there are only certain times when Dean willingly accepts “sappy lovey-dovey crap,” and he doubts now is one of those times.
So instead he says, “I read in the newspaper the other day that a twenty-two year old woman married an eighty-nine year old widower.”
He delights in the way Dean laughs, unrestrained and wholly affectionate. “That, Cas, is what we call a gold-digger.”
“Gold isn’t nearly as valuable as it once was,” he says. Dean laughs again.
“She just wants his money; the chump probably knows it, but who can resist a trophy wife?” Dean has moved away from the mirror and is pulling a shirt over his head.
“Perhaps I should ask Sam to make me a lexicon,” he ponders aloud. He’d asked Sam once before, but he’d thought Castiel had been kidding. He was—mostly—at the time, but maybe he should consider it more seriously. Over twenty years—and that’s an exceptionally long time, he thinks, all things considered—with Dean and he still doesn’t understand half the references and colloquial terms Dean is fond of.
“Talk about a boring read.” Dean snorts, fingers fixing his belt in place. “There’re still plenty of Vonnegut books you haven’t read yet if you’re looking for something to read.”
Castiel doesn’t tell Dean he’s not very interested in dystopian literature; he’ll let Dean have this and enjoy the way Dean finds it fascinating, but he’s content to keep reading obscure history books.
Dean appears both younger and older because of his hunting—which he still does more often than not. Castiel goes with him because there’s something solid and reassuring about being at Dean’s side. Dean never pretends having him around is the same as it was hunting with Sam, and Castiel would never want or ask him to, but it works well enough for both of them.
In some ways Dean is still limber and strong, all quick reflexes and quicker distrust of unknown people. But in others—the weight of the world on his shoulders and in his eyes, the lines ground deep around those eyes and in the set of his mouth—it’s like Dean is as old as Castiel is. And that worries and pains him more than anything else.
Castiel wonders if humans are ever grateful their lives are so short, so fleeting. He thinks they should be. When you exist for thousands of years—especially when you keep dying only to be resurrected—you realise that non-existence is mostly relief. Especially for humans, most of which end up in Heaven. And for those who get stuck in Hell, they probably saw it coming.
Suddenly, he wonders if maybe it’s time to really speak about this—truly and seriously—and before he can persuade himself out of this conversation, he starts talking. “I keep seeing you get older and it terrifies me,” he admits softly. “I keep waiting for the human heart I can always hear inside this body to catch up, to weaken and wither away, for my skin to get drier and rougher—though I know it won’t happen. But I can’t help but wish I could give you what Sam has, someone who will grow old with you, at least in theory, and someone who will follow you into the afterlife, and seek you out in Heaven. But I can’t, and out of everything, that’s what I’m most sorry for.”
Dean’s face contorts with so many different emotions—surprise, tenderness, wariness, disbelief—that Castiel has trouble placing them all. Eventually, Dean makes his way over to sit beside Castiel on the bed they’ve been sharing, flipping Castiel’s hand over with his so they’re resting palm to palm. “Cas,” Dean murmurs. “I know it’s kinda shitty and not what anyone has in mind when they think about where they’ll end up and who’ll they’ll end up with.” He inhales sharply and sometimes Castiel has trouble reconciling this man with the thirty-year old who would laugh off every serious conversation people tried to have with him.
“But,” Dean goes on. “How often has my life been normal? And sure it would be nice to have all those things, but they’re not you and I’d still rather have you. So we just keep dealing.”
Castiel feels a rising pressure just under his sternum, lets it expand and then collapse in on itself as he sighs in relief. He falls back against the mattress Dean follows the momentum, landing half on top of him.
In typical Dean fashion, he doesn’t let the moment end with sensational emotionalism. “Besides, I can always tell people you’re my trophy husband if they try to get in our business,” he jokes.
Castiel smiles against the curve of Dean’s neck because nothing in their life will ever be easy, but it’s theirs and it’s now and isn’t that what people are always saying matters?
Dean doesn’t hunt anymore. He still does research, of course, but he’s passed all the gruelling physical work onto Prerak and Sonya, a pair of hunters he’d found working the same case as him one day in Nebraska. They’re difficult and often grate on Castiel’s nerve, but they’re efficient and Dean likes them. He’s sort of a mentor to them now, Castiel supposes. He and Dean are living about forty miles away from Sam in Pennsylvania.
One time Prerak had had the nerve to question his relationship with Castiel. No one really talks about it but Dean had, quite firmly, put the kid in his place and made it clear whatever's between him and Castiel is absolute and absolutely off-limits.
Dean is currently talking to them on the phone about a case involving a rugaru and Castiel is folding the laundry. Dean claims it’s Castiel’s duty since his body is younger and more accommodating for manual labour. He does his best not to flinch when Dean says things like that, but he’ll never really get used to it—to loving a human in such a fierce, undeniable way, and living with him in a quasi-domestic life. They’ve even got a cat. He’s large and grey and missing a leg and he likes to tear up the throw pillows on the couch—“In his defence, those pillows are fugly and I dunno why Sam bought them—well, no that’s probably why,” Dean says—but Castiel’s taken to him quite well.
When Dean hangs up, he looks over at Cas musingly, pushing away a coffee mug. “You know,” he says almost absently, “if I had a real job, if I ever had a real job, I mean, I’d be old enough to retire by now.”
Castiel hums his agreement because he doesn’t know what else to say. Dean goes on to say, “I bet we would be that retired couple who lives in a cabin next to a lake. I could sit outside and threaten to shoot any meddlesome kids who show up with my shotgun.”
“Meddlesome children? What, are we in Scooby Doo?” All right, Castiel might have also taken to Saturday morning cartoon reruns.
Dean snorts. “You keep getting cheekier the older I get.”
“It’s because I have to continuously put up with you complaining about your aching joints,” he returns. If Dean wants the mood to be light, Castiel will go along with it—because he doesn’t know how much longer Dean will want the mood to be light, or will want anything at all.
“I should make you sleep on the couch with the cat.” Dean has abandoned the kitchen table to join Castiel in the living room. He presses a hand to Castiel’s hip and Castiel smiles to himself because Dean is still warm and beautiful and he wants whatever Dean will give him.
“You’ll get cold,” he says, and gives up on the laundry to turn and face Dean. Sixty-six years old and still full of fire. Maybe he’ll be like one of those legendary storytellers who live far longer than anyone expects. A woman in Mozambique died a few days ago at the age of a hundred and eighteen. That might be pushing it in Dean’s case, and Castiel does his best not to think about it, but Dean is good at surprising people.
Castiel knows that even though his body hasn’t aged, he has—and it shows. His eyes get duller more quickly and there’s the thick taste of ratty cotton in the back of his throat, the way his hands shake when something rattles him.
Dean doesn’t comment on any of it for the most part, and Castiel is grateful. They don’t go out often. And when they do, people really do assume now that Dean is Castiel’s father and—it’s so far from true Castiel would laugh if it didn’t hurt so much. Granted, his Father is considerably more disappointing than Dean, but he lives with that the way he lives with pretty much everything; with varying degrees of success and blood alcohol levels.
He doesn’t have an adequate way to define his relationship with Dean, or what Dean is to him, other than—everything. But even that is too simple and structural, so they avoid definitions and avoid going out and avoid almost everything except each other and their weekly dinners with Sam and his wife.
All in all, it’s still better than being stuck in Heaven with a bunch of power-hungry angels who haven't learned how to live with their Father’s flaws.
Dean avoids physical contact of all sorts now more than ever. Castiel can read in his face that the man feels old and tired, ashamed of the way he ages. Castiel wants to tell him not to worry, but it wouldn’t change anything, he knows. So he makes Dean dinners of macaroni and cheese and lets Dean put himself in bed so he doesn’t fret about Castiel watching him struggle with it.
Every day he grows heavier with the knowledge that Dean’s time is coming. Heaven will be kind to him and will love him, but it’s just memories, so it will never love Dean like Castiel does.
Nothing has ever felt so overpowering and he knows he’s been right all along—Sam’s been right all along—and it will end in disaster and drowning, but he’ll keep dealing and he’ll keep going.
It doesn’t make anything easier, but the way Dean still smiles at him when he thinks Castiel isn’t looking helps a little. It’s something to hold onto in the cold of the night while thunder crackles around them.
For all Dean’s bravado and shame, he still moves closer to Castiel under the covers and Castiel revels in it, savours it so when it’s gone—when Dean’s gone—there’s more than bitterness and unending grief.
Dean would probably find a way to kick his ass even from in Heaven if he found out Castiel was moping around pathetically. And Castiel can admit to himself it would be dishonouring the progression of their relationship and the people they’ve become.
Dean is in a deep sleep and usually Castiel rests so he can stay beside Dean at night. But he’s having trouble relaxing tonight, so he whispers, “I love you,” into the dark.
Dean doesn’t reply, but he’s never needed to. It’s never negated the meaning Castiel gives to it, and he’ll never let it.
There’s a soft, raspy breath against his shoulder that’s answer enough, despite what the future will bring—or take away.
At the foot of the bed, their cat shifts, yawning, and Castiel smiles to himself.