I.

Castiel knew what the disgusting weal on Dean's right arm was. Brand of darkness. Scar of the first slaughter. The Mark of Cain. Dean had wanted him to see it, had purposely brought that filthy sigil close to his face. Rigid with fury, he glared.

Dean watched him carefully. Cas could crush his arm, and right now he wanted to make a point. Cautious respect flashed in his eyes as Cas gripped that branded arm tight enough to cause pain.

"What have you done?" Castiel growled.

Dean's eyes broke like window panes, and through the cracks, terror screamed. Then he whipped his arm loose and pulled down his sleeve. "It's a means to an end," he mumbled to the pavement.

"Damn it, Dean..." Castiel screwed his gaze into the man. That end he spoke of? It was his own. Dean's lust for martyrdom overwhelmed both will and brain. Cas knew that about him. But this was the worst possible moment to learn he'd set in motion yet another plan for self-immolation.

The parting glance Dean flicked him over the roof of the Impala was hot with fear.

X

Castiel, only vaguely aware, reentered his motel room. He had the curious sensation of time stretching like soft taffy to accomodate the speed of his racing thoughts.

Because of the Fall, he was no longer connected to the power of Heaven. He could not enter dreams. Without his wings, he couldn't even watch over Dean. That meant he had no way to monitor the progression of Dean's inevitable disintegration.

Even with those limitations, being an angel was still better than being human. Not that he'd hated "Steve"—he'd learned so much about the simple dignity of honest work, the poignancy edging every human emotion, so ephemeral, so violent. But Dean had treated Steve like a cute kid brother. Did all but pinch his cheek.

Castiel had swiftly realized that so long as he remained human, Dean's pain was off-limits. That meant Dean was off-limits, because he, as Steve, was just one more person to protect. Just another stone in a drowning man's pocket.

Well, he had grace again. Once again, he was strong enough to lift the Righteous Man, and the Righteous Man responded. All well and good—except the grace he'd stolen was temporary. Dean's willingness to make himself vulnerable to him, then, was also temporary.

Cas stared blindly at the wall, papered by maps. He couldn't let himself be distracted by thoughts of Dean now. He had to consider the matter of Metatron.

They'd met. The Scribe's proposal: that Castiel serve as a puppet leader for those angels who currently found him... unpalatable. Once Castiel gained the rebels' trust, he would, at the proper time, betray his army to Metatron. The Scribe surmised the naturally submissive angels would follow him without a fight. Once he gained the throne of Heaven, he would reward Cas with a source of ever-renewing grace. Or, even better, he would return what little remained of his own.

At the time, Castiel had not even considered it. Regardless of his personal opinion of the angels' willpower, he'd never forgotten the disaster he'd made of his previous attempt to lead. He'd decimated the angelic host, and worse, murdered humans by the score. Now that Dean had gone and branded his arm, however, the idea of leadership not only had merit, but urgency. He didn't mean to take Metatron's deal, of course—he'd never betray his people—but, if he stayed in the fight, he knew he'd find a way to make the Scribe cough up that grace. Even if it wasn't his own, he would take anything he could get to save Dean.

Every sentient being's greatest strength was also its greatest weakness. In Castiel, that double-edged sword was his determination to keep going until every option was exhausted. So what happened next couldn't even be called a decision, because really, he never had a choice. To save Dean, he had to save the angels.

Time snapped back into its normal flow. Cas surged and tore the maps from the wall. The angel blade bit his inner arm, bisecting flesh and vein. Holy light sang from the lips of the wound as his vessel's blood drained into the collecting bowl, its scent mixed with angel energy, floral and cloyingly sweet.

Like everything else on God's green earth, the knife's edge, the pain, the smell of blood, made him think of Dean. Dean didn't mind the knife. Though he'd never turned cutting into a hobby, he also never flinched from the pain. It was something he could trust, something he could control. A distraction from life's more abstract torments. He had other methods when things got bad—more effective, perhaps, but less palatable.

For his part, Cas wished Dean would ladder himself with cuts, rather than seek out... those strangers.

Back when he'd first met Dean, before the hunter taught him about privacy, he used to watch over these encounters. Still more light than man, all he could do was tip his head in wonder at the sight of Dean, grunting and sweating, the crown of his skull pounding against a car door or his cheek barking on bricks as the stranger behind him plunged and reared. The congress was always rough. Dean always bruised, tore, bled. The only saving grace was he didn't seek it often. Not nightly, not weekly, not even once a month, but whenever things got bad, as they always did... as they were now... he sought himself a stranger.

The Castiel made of light wanted to understand what purpose this activity was meant to serve. It was obviously not procreative, and Dean seemed to derive no enjoyment from it. So, cold as a scientist, he studied Dean's past. With Heaven's power, he moved back in time and watched boy Dean, out of money, his little brother sick or hungry, first agonize and snarl over the necessity and then, once it had become just another means to an end, shrug into his coat and say, "Go to sleep, Sammy, and I'll be back with some food."

Even as innocent as Castiel used to be, no one had to tell him that Dean was far too young. His johns were predators, men who fantasized about fouling something pure. They were not kind.

But boy Dean had done what he had to do, and Sammy thrived. As for why he sought the same out now...

The bowl brimmed with blood. With sure gestures, Castiel painted the Horn of Gabriel on the motel wall.

Dean couldn't have known, when he took that Mark, that he would one day become the demon he'd always feared he'd be. On that day, freed from pain at last, with no need of Castiel, no responsibility for Sam, he would cavort in a Paradise of death instead of flowers. Without his free will. Unless Cas stopped it.

The Horn began its pure, summoning tone.

II.

"Keep an eye on him," he'd heard Cas order Sam.

Dean stared inflexibly at the road unspooling in the Impala's headlights. God damn that interfering sonuvabitch anyway. Sam, riding shotgun, kept feeling at him, like that big brain of his had sprouted tentacles tapping at Dean's temples, begging him to open up. Fat chance.

A couple years ago, after Cas donned the loonyform and buzzed off to bliss on bees, Sammy had sat there in the hideout cabin, doing that same telepathic tapping thing. Sorry, Cas had said before he left, all simple and radiant like a toddler. Yeah, he'd gone batshit crazy, and he was SORRY!

Leaving Dean alone with Sam, who, with his shiny new mind, decided it was time to talk out every painful thing that had ever happened to them, like hey, we're already bleeding, let's lance the abscesses in our souls and be rendered clean by the fire of our despair.

Brilliant, Sam. Dean wanted nothing to do with such a project. If he started sawing through the membranes of those walled-off old hurts, the amount of pus released would drown them both. The only purification he needed came inside a whiskey bottle.

But Sam, much like his old buddy Lucy, just. Would not. Shut up.

"You told me about... what happened to you in Hell. When you were ready."

Dean slugged some whiskey. He wasn't there yet. Once his lips went numb, he could start in on the serious drinking.

"You listening?"

"Yeah," Dean said. He swallowed the liquor.

Dammit. Sam always was one to talk it out, but Dean didn't know if he could bear to hear it. What his brother went through in the Pit. What he, in spite of everything, had been unable to save him from.

Sam shifted noisily in his chair, swinging his shoulders away from his laptop where he was doing research on who the fuck cared, but Dean kept his eyes on the level of liquor in his bottle. There was enough. If there wasn't, he'd made sure to pick up a few cases of beer on his last run into town. He'd be fine.

"Remember that time you were gone two months? Dad said you got lost on a hunt?" Sam asked.

Actually, he'd been in a boy's home. A john rolled him for the seed money Dad had left them to live on. Dogged by the thought of returning to Sammy empty-handed, Dean tried to swipe some food. He probably would've stepped on the shoplifting charge since the motive was so obvious and so pathetic, but the clerk had a bug up his ass about the underage cowboy working the pavement outside his store. Dean never forgot what he'd said to the deputy: "Lock that little faggot up and put the fear of God in him." Dad said something similar when he'd left him to serve his time. He didn't blame the man. He'd deserved it.

Sam, talking. "Lucifer, he told me. Wanted to make me feel stupid, I guess, show how honest he was in comparison. He told me where you'd really been." Sam paused for drama before he brought the hammer down. "He, uh, told me how you got there."

Dean considered just. Not responding. After a sip from the bottle he said, "Easier on the karma than mugging and quicker than a con. Kept you in Jujubees, Sammy."

"Dean. You don't have to explain anything to me. I know why you did. How it felt? I... learned." Words failed him then, which was just fine, because his voice had started to see-saw like he was having trouble keeping control, and that was not something Dean could midwife him through. Not at all.

Whiskey sloshed into a glass. Dean muttered, "Wish I coulda killed him for you."

Inside, the cut Sam inflicted bled: I'm sorry. I'm so, so sorry. I shoulda kept faith. I shoulda never walked away from you. What the Devil did to you in the cage? That's on me. One more on me.

"That goes without saying," Sam said in unwitting reply to Dean's brooding thoughts. "I just wanted you to know. That I... I know. I understand."

"And I never, ever wanted you to understand a goddamned thing." Dean shot the glass in a gulp.

Now, Dean swallowed to drown out the low, murderous hum of the Mark, resisting the urge to plow his fist into his brother's face and close those anxious puppy eyes with bruises.

Cos, sure. Sure, Sam totally understood. Years of Satan reaming out his ass, because that's what happened to you in Hell. Not much gray area there, but Dean? Hell, he'd sold his! Different things, baby bro. He'd trolled for it, invited it, played up to the ones who wanted him to like it, acting that maybe-sorta-kinda edged into truth sometimes, if the guy smelled right, moved right.

Which, while confusing enough, wasn't even a touch on whatever supernatural-beastie hard-on he had going for Cas, if that even belonged in the same category. Wasn't a man, wasn't a woman, wasn't a human, and apparently that moved his furniture in a big way because it took him years to stop staring at the dude's lips. So what did that make him? Did Tumblr have a hashtag for what he was?

Dean tried to make himself feel better. It's not like he sweated it all the freaking time. He figured he was straight. Straightish. Straight enough. When "fun" was what he had in mind, he found himself a woman.

But every once in awhile, even though he really had no reason and no excuse, he still trolled. Told himself, quick money. Sought out the mean ones, their mangy hides tattooed with pictographs of all their sins, demons without the smoke. Humped for them like a bitch dog, made sure they hurt him. Didn't pray to Cas, at least not that he knew of, but afterwards, lying there in the dark or huddled up in an alley, sore, burning, wetness in his boxers he refused to think about, he'd feel the angel's touch on his brow, cool and fleeting like a kiss, and it would take away the pain.

Sometimes he hated him for that mercy.

Fuck Tumblr. Not even the lore had a name for the kind of monster that made him.

He beat the steering wheel, shaking off pins-and-needles from the Mark, which pinched him like a crab whenever he needed a distraction from his thoughts. Distantly it occurred to him that he could get to like the damned thing. It seemed to be on his side, if nothing else.

Too soon, they were pulling into the latest parking space at the latest motel.