They didn't believe it at first.
The stares and whispers were more than he was used to, but he ignored them, spending is days in the infirmary with Elspeth, trying to ignore her. That was harder.
Then they started coming to him, the God fearing ones, the ones who were never without a bible in their pocket. He told them all the same thing.
"I'm no angel."
As his back healed and he could move around more, he spent his time on top of the roof of the small cabin that had been dedicated to trying to heal those that came in. All too often the cure was a bullet in the head.
Dean didn't come to see him all that often, only when there was a tactical decision to be made. He still had his mind, although he could feel his celestial knowledge slipping away more and more as each day passed. He told Elspeth that once and she only looked at him sadly.
She had kept some of the midnight black feathers that had fallen out of his wings before they combusted. The others had taken the rest. Cas couldn't bring himself to care. They were a remnant of another life, of something that he couldn't go back to, so why torture himself by leaving reminders constantly around?
"Why are they black?" Elspeth asked. Cas never initiated conversation with anyone other than Dean, so if she wanted to talk then she had to start.
"Many reasons," Cas replied softly, looking out the window and up at the stars. Maybe he could pretend they were his siblings, if he tried hard enough. He didn't have to ask to know that she was talking about his feathers.
"So tell me some." The younger woman never took no as an answer, and if he didn't answer then she would pester him about them for another week.
"I don't want to." He would risk the pestering.
"How come?"
"It would remind me of things that I cannot have."
Elspeth raises her brow, obviously not expecting that answer. "Some of these are scorched."
"That's what happens when you put them too close to fire."
"Angel wings can be burnt?"
Cas sighed. "By two types of fire."
"Which ones?"
"Hell fire and holy fire."
"Wow. Okay then. How'd you get burnt?"
"Elspeth I don't want to talk about this."
Elspeth scowled. Cas sighed again. He knew she'd get the whole story out of him somehow, so he decided just to get it over with.
Half a bottle of whiskey later, he was ready to talk.
"An angels wings are meant to be white you know. You humans got that right at least. We are light and energy and will and wrath and righteousness. Nothing physical, an angel in the celestial realm is distinguished by their traits; Uriel was ambitious, Rachel was loyal, Balthazar was fun-loving, much like Gabriel. Anael loved too much while Hestor was sceptical." Half the words were slurred.
"What was yours?" Elspeth asked quietly. She looked like she wanted answers but that this wasn't how she wanted to receive them.
"I don't know what I was in the beginning, but near the end I was probably recognised for my pride. Or maybe my despair. You see, I changed. Angels aren't meant to change, Elspeth.
"My wings were white once."
Elspeth nodded slowly.
"Do you know who the first angel with black wings was?" When she shook her head, he continued. "But you can guess, right? Lucifer was the first among us to commit a sin, and he was the first to be branded. When I led my garrison in the depths of Hell we all knew that we would not come out untouched. Hell-fire is poison to angels, and I lost far more of my garrison than I would have expected rescuing Dean's soul."
"You rescued Dean's soul from Hell?" Elspeth sounded shocked.
"Yes, it's how we met. Well, how I met him. He doesn't remember it. Yes, that is the first type of fire to scorch my wings. It blackened the edges and curled them. Then when Lucifer trapped me in a ring of holy fire, to try and convince me to come to his side, that is where this happened." Cas points to the missing parts of feathers. "Only holy fire can burn away an angels wings. And both times, I burnt for Dean. I burnt myself escaping that cage, scarring myself permanently in the process, something that even Lucifer didn't predict because it is so out of character for an angel to knowingly harm themselves he left me alone and unattended. But I wasn't fully an angel then, I'd already started Falling. So he couldn't predict my actions and I escaped."
Elspeth was looking slightly sick and he hadn't even told her half of why his wings were black.
"But those were just the edges, and in the end they didn't matter. An angels wings are layered you know. The quills, the ribs, the primary, secondary, tertiary feathers and under that the down. Each one represents a different sin. When I killed my first sibling my quills were dyed black, when I lost my faith in my Father my primaries were gone. Falling made the majority of them turn, and by that time I only had white down. And then that was gone too, the last to change, spurred on by my ultimate blasphemy." Cas sighed, and shook his head wincing when he stood. "I'm going out."
Elspeth didn't say anything against it and Cas tried to ignore to knowing look in her eyes.
/\/\/\/\/\
The pain medication that Elspeth gave him was good for taking away the almost constant splitting pain from his back, but more importantly, it made him feel good for the first time since he was an angel innocent to Heaven's plans.
"Castiel!"
Cas sighs, looking down at one of the more vocal members of the group who were convinced that he was God's gift to them.
"Castiel you can't ignore what you are forever!"
"I'm human now! How many times do I have to tell you," the last sentence in a murmur.
"Hey! Leave Cas alone," Dean said as he jogged up to stand in front of the lady who was standing under Cas.
"He needs to accept who he is," she argued.
"You need to accept that he isn't answering your questions. Now leave."
The woman scowls but reluctantly walks away slowly, glancing over her shoulder every now and again. Cas is about to thank Dean, but the other man just shoots a displeased look at him. "What are you doing up there? Come down before you fall down," he says over his shoulder as he walks away as well.
Cas silently swallows another two pills.
/\/\/\/\/\
Cas confesses what black down means to Elspeth four months later when he breaks his foot.
Dean hasn't returned to how he previously treated Cas before he Fell, so Cas isn't quite sure why the down that Elspeth still has is still black. It still reflects his mind-set, even if he's human now. His feathers are still an intrinsic part of him, and his species is still angel even if his physical body and soul are human. He tells Elspeth this as she gives him a precious shot of morphine from their stash. He doesn't tell her that he has at least three times more in the stash under his floorboards than what she has here.
Elspeth pauses, and Cas can tell from this that she still hasn't forgotten their conversation and how he avoided telling her the last part, no matter how she asked. "Really?" She finally asks.
"Yes, really. Which is why I'm confused as to why my down is still black. I mean, Dean hasn't spoken more than three sentences to me any day in nearly five months. He never comes to visit, he never talks about anything other than to ask my tactical advice, and half the time he ignores that."
"That is probably because you're high half the time, and I still don't know where you get your drugs from because I don't see any from here going missing."
Cas smiles mockingly and doesn't tell her how he was collecting medicine so when they ran out he could give them more and make the supply last longer.
"So yes, I'm confused as to why it's still black. I mean, really, what has Dean ever done for me? What has he done? Nothing. Nothing at all. And so why do I feel this way? He is the source of my exile, the source of my humanity, the source of the constant pain that I carry around because my wings are gone."
"You still feel that? Like, not just metaphorically but physically?"
Cas laughs, and Elspeth pulls away at the sound. Cas realises that he might be being a bit looser than normal because of the extra morphine in his system, but he doesn't really care right now.
"Come on Elspeth. You can guess what the ultimate heresy is. More than losing my faith or killing my siblings. Guess."
Cas sees the moment that she realises. The look of dawning comprehension followed by a look of pure pity. Cas shrugs. Now that Elspeth knows more about him than nearly every other human, he looks her up and down again, with a new, critical eye. He's heard of other people talking about how sex is one of the only things they have left, and while he had been hoping and praying in some deep part of himself than Dean would help him lose his virginity, he just felt a rush of self-loathing when he thought of how hopeful he had been.
She's his first, but certainly not his last.
/\/\/\/\
Sometimes when Elspeth hears of whoever Castiel was sleeping with now, she retrieves his feathers from the shoebox under her bed. Every part of the feathers are still black, and she simply shakes her head over them, not knowing what to feel for the fallen angel who had tumbled into her clinic and into her bed.
Mostly, she just feels sorry for him, especially when she sees Dean coming out of whoevers cabin, but the worst time was when she saw Cas's reaction when he had seen Dean. The fallen angel had had no reaction whatsoever, but Elspeth could see the despair and pain etched into the corners of his eyes, the way his laugh was too loud and bright, and how he himself would often be the one leaving a cabin that was not his the next day.