A/N: Warnings for mental illness, abuse, implied rape and and just general darkness.
Castiel's gone. Sam doesn't seem bothered, considering the angel used to wander off often enough before, and always came back without coming to any harm, but Dean… Dean knows better. Purgatory changed Castiel, for the better in some ways. He's more focused now, less prone to indecision and flying off, but quieter. More broken. It scares Dean, is he's brutally honest, scares him not with Castiel might do, but with what Cas might do to himself.
When evening falls, and the street lamps begin to flicker on through the murky motel windows, Dean puts his foot down, snaps at Sam to stop telling him to relax and get his fucking gun because they're going to find Cas.
It takes them an hour of walking and searching to find him, and by that point even Sam's stopped telling Dean he's overreacting, because the trail of, "yeah, I saw him, beige overcoat, right?" is leading them towards the backstreets of the town, dark and dirty and not a place for absent-minded angel.
The nearly miss him, in the end. So, so nearly that it makes Dean sick to think about. It's only because Sam stops to zip up his jacket that they hear the damp, wheezing breath from the alleyway just behind them.
Castiel's a mess. Blood and bruises and ripped clothes, curled up in the dirt and piss at the end of the alley – and he's smiling. "Cas?" asks Sam nervously, edging down the alley and touching Cas's shoulder, like he expects the angel to bite.
"Sam, Dean," the angel rasps, eyes blinking open at their approach. He pushes himself into sitting position, gaze unfocused and blood clotting over a spectacular bruise on one cheek. "What brings you here?" There's something at the corner of his mouth, a whitish glint before he sweeps his tongue over cracked, swollen lips carries it away.
Dean's stomach twists. "We were looking for you, you stupid bastard!" he growls, panic lending anger to his voice. Sam eyes him with disapproval from where he's knelt by Castiel, trying to ascertain the extent of his injuries, but Dean ignores him and curls his hands into fists. "What the hell happened to your whole 'no conflict' thing, huh?"
Castiel doesn't seem to hear him – he's staring at his left hand, at the two fingers twisted at awkward angles, and flexing them gently. Dean's had broken fingers before, knows how badly they hurt to move, but Cas doesn't seem upset. He's just smiling gently, eyes soft and happy.
It's fucking terrifying.
"Cas!" snaps Dean, and the angel's eyes focus slightly, looking up at the hunter.
"It's not conflict if you don't fight back," he says calmly, with an expression that can only be described as beatific, and smiles evenly in the face of Dean and Sam's horror.
Later, when they're back at the hotel and Cas's fingers are set, his cuts stitched and bandage, and Sam's out grabbing food, Dean says, "You come to me, you understand?"
Castiel isn't listening, is pressing three fingers, hard, against a bruise on the fleshy underside of his arm. "Cas!" says Dean louder, and the angel looks up, head tilted and eyes hazy. "Look, I don't know what the hell tonight was, whether… whether this is something you want now, or… but, you need this again, you come to me okay?"
He hates the idea of it, of hurting Cas, of using him like that – but he hates the idea of Cas wandering the streets and ending up in a bloody, broken heap down a back alley somewhere even more, so he'll do it. God help him, he'll do it, break Cas down with his own hands as if he were a soul on the rack if that's what needs to be done, because it's better than the alternative.
"It's okay, Dean," says Castiel absently, attention already drifting back to his injuries. He pulls his shirt up a little – his own clothes were wrecked, he's wearing some oversized thing of Sam's now, buttons done up clumsily in the wrong order – and picks curiously at the stitches running across his stomach. "I know you're busy. Lots to do, Leviathan to hunt. It's not difficult to find people, I can always-"
Dean grabs Cas's wrist, drags it away from the thin line of red and black, twists the fingers of his other hand into the angel's hair and forces Cas's gaze upwards. "You come to me."
"Dean," whimpers Castiel, and the way he says it – like a prayer, a blessing – turns Dean's stomach, but he forces himself to tighten his hold until he knows Cas's scalp must be aching, knows there will be new bruises for Cas's collection in the shape of his fingers.
"Do you understand?" Dean growls again, as much authority as he can muster ringing in his voice, and Cas nods frantically. The motion pulls at his hair, tairs a few stands out, but he hardly seems to notice.
"Yes. Yes, Dean, yes," he promises, and his eyes are clearer than they have been in months, bright and laced with pain.
"Good," says Dean, letting go of him, and when Castiel looks up at him with awe and gratitude, Dean feels something inside of him shatter, the pieces twisting around his heart and digging into his lungs, making it hard to breathe. He does so anyway, nods, manages not to be sick, wonders how in God's name he's going to do this, because he doesn't think he can, but he has to. "That's- that's good."