A/N: Sorry this is late!

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And thanks to SPNxBookworm for being my eternal moral support. :D

Unbetaed, so all mistakes are mine.

Three: Never Change

"It's me, Sammy."

Sam swallowed. Dean was wearing the same bloody clothes from before, but the cuts on his face were gone, leaving it relatively clean. His hair was matted with congealed blood and the Mark of Cain shone red, its tail visible from under Dean's rolled sleeve. Perhaps it was Sam's imagination, but the Mark seemed to be glowing a little too.

His gaze fell to Dean's eyes, which were black, and he wondered if this was some sick joke. Had Crowley done this to Dean? Purposely grabbed the opportunity to make him a demon?

Sam's grip tightened around the blade in his hand.

"Sam," said Dean, "we need to talk about this."

Sam snorted. "You think?" He didn't lower his weapon.

Dean raised a hand again, but not to restrain Sam this time. "You – you've gotta help me out, okay? I know you wanna kill me, but… I don't know—"

"Are you sure?" Sam snarled.

"Sam, it's still me," said Dean. "And," he paused, and licked his lips, "you can't kill me with that."

"What do you mean?"

"I'm a Knight of Hell," Dean breathed. "Crowley came to visit me. He told me something, okay? But you've gotta listen to me first."

Sam wasn't sure he heard that right. His jaw slackened as he saw the demon, the black eyes doing nothing to make him believe that this was his brother standing before him. But Sam knew, deep down, that this was, indeed, Dean. He had known it before Dean had turned around to look at him, and before Castiel had confirmed it, but no… this was not possible. His big brother couldn't be a demon.

He shook his head. "How do I know, that if I just sit and listen to you, that you won't kill me?"

And then Dean's gaze met Sam's, his eyes locking with his brother's. Sam watched in wonder as the black in Dean's eyes flickered away, giving way to familiar green.

"Because," Dean said in a low voice, "no matter what, I ain't gonna hurt you, little brother."

~o~

Hunger coursed through Dean like gigantic tidal waves. It was something he had never felt before — going beyond physical hunger, and making his palms itch for the smooth hilt of the blade in them. A voice in his head roared at him, to get out of the bunker, from the confinement of his brother and Castiel, and to kill. He wanted to start with Crowley, though. He wanted to kill him slowly. Starting with his gut, in a smooth, incision-like, cut, savouring the blood that oozed out…

"Dean?"

Dean snapped out of his reverie as he saw Sam's eyes trained on him. They'd settled in the library, with Sam still holding up his blade in defence, and extremely cautious. Castiel seemed wary too and his hands were both on the table, although he continued to look at Dean in a scrutinising gaze. Dean could see Castiel's halo. It was weak circle of light around his head, golden and pure in every way that sent Dean's skin crawling.

He supposed he should be offended that Sam and Cas didn't trust him not to attack, but he didn't care. He knew that had he been human, he'd have been hurt, and he'd have tried to joke around it, but right now he was so used to Sam not trusting him — whether he was human or demon — Dean couldn't give a damn. And it made him feel good. He understood why Castiel hadn't been human for longer, now. The world was a better place when you couldn't feel.

"What did Crowley say, Dean?" Sam pushed him, his voice cutting through Dean's thoughts again. Dean had already explained to him about the Mark, and how, according to Crowley, that was what had tethered him to life — in a different form.

Dean sighed. "He says I'm gonna be evil."

"Because demons are practically cuddly and innocent?" Sam questioned him sceptically.

"No, I—" Dean didn't want to tell him. He didn't want to reveal to Sam that Crowley had warned him that in a few short months, he would not be able to remember how to be human. That he'd become like Abaddon, or Ruby. Or Azazel.

Castiel narrowed his eyes at Dean, speaking for the first time in a while. "I suspect I know what Crowley said."

"What?" Sam asked him.

"Dean's soul is demonised, but he, as a whole is not. He still remembers us — and he remembers being human. But he will lose his human memories as time passes. And that won't take very long."

Dean cocked an eyebrow. "How did you know that?"

"You aren't the first demon I've encountered."

"So is that what Crowley said?" enquired Sam.

Dean nodded. "Yeah, he said that. I take it he's not lying, then."

"He isn't," Castiel replied.

"Well," said Sam, "it's a good thing that I can cure demons, then. We'll get you back to normal in no time, Dean."

Dean shook his head. "No."

"Why?"

"Just… no, Sam."

Sam looked confused as he ran a hand through his hair. "I – I don't get it. Why? It'll take all of eight hours and we can get rid of this whole mess."

"Sam," Dean licked his lips, "you didn't complete the trials. You almost died after that last one — and you would have died if Gadreel, and then Cas, hadn't healed you. Cas doesn't have all his mojo to heal you now."

Dean knew he shouldn't be able to feel anymore, but the horror of the day when he thought that Sam would die, still stood out at him. He remembered praying, remembered being taken for a ride by Gadreel, and remembered going into Sam's head. He remembered the doctor's words, about how it was unlikely that Sam would survive…

… and, "Same circumstances, I wouldn't."

A wave of fury flashed through him and Dean curled his palm into a fist below the table to stop the First Blade from flying into his hand. He could see Sam and Cas looking at him, but before they could say anything, Dean stood up.

"You know why else I don't want you to cure me, Sam?" he asked, his own voice sounding like it was coming from afar, "Because no matter what I do to save your ass, it isn't good enough for you and I don't want your fucking ungrateful demon-infected blood in me when I'm human."

He barely registered the hurt on Sam's face as he walked away.

~o~

Castiel watched Dean leave; intrigued by the way Dean's eyes had suddenly flashed black and how he had changed all of a sudden. He had seen Dean's fingers curling, and had noticed that he had craved the Blade, but was glad that Dean could control it enough to walk away before he took possession of it.

Beside Castiel, Sam sighed. "I'm going to bed." Castiel could hear the hurt in his voice.

"Sam," he said, "your brother is…"

"He's a demon, I know." Sam huffed a small laugh. "I guess I shouldn't be offended then."

"No," Castiel said, "you should understand that demons are not like angels — they do feel, and not in the way that you do. All their emotions are extremes. They lack remorse or repent. They do not think about what they've said. They use words and their own anger as a weapon. Dean was just—"

"— trying to get back at me," Sam finished for him, nodding. "Fair enough."

"No, Sam," said Castiel. "He did not do that intentionally. He was craving the Blade again. It came out on you."

Sam frowned at him. "How do you know that?"

"I've heard tales," said Castiel. "And I also know that you are the only person who can anchor him from what the Blade does to him."

"The Blade has already done everything it could." Sam's face turned bitter as he clenched his jaw, hand going to push his hair back. "I should have put a stop to it when I saw it. I knew that fucking Mark couldn't be good. Should have convinced him to get it off. In the end, Abaddon wasn't even the fucking problem." Sam shook his head. "She only got on our asses when she realised we were out to kill her. And now, I'm going to fucking kill that Crowley."

Castiel didn't object to that. He watched Sam get up, and Sam waved at him before making his way to his own room. Castiel played with the lamp on the table, flicking it on and off, remembering the gentleness with which Dean had kissed him, and knowing that the same tenderness was probably gone from Dean. But Dean actually wasn't too different from the way he was at the crescendo of his Blade-related high. Maybe, he, Castiel and Sam, could actually help Dean by getting through to him.

He didn't know how long he'd been thinking, when he heard footsteps from down the hall. Castiel stiffened, and then his eyes caught Dean as he emerged. The table lamp was switched off, and so were the lights on the war room, since Castiel hadn't needed them. It wasn't entirely dark, though, and Castiel flicked the light switch again.

Dean was expressionless as he came and sat down opposite Castiel at the table. "Hey."

"Hello, Dean," said Castiel.

Dean smirked, and in the dim light, Castiel could see that his eyes were green again. "I don't need to sleep anymore," Dean said. He sat back and sighed. "God knows, that feels awesome. More time to kill fuglies."

"You have the urge to kill again," Castiel remarked.

"So?" Dean asked him. "I mean, yeah, it bothered me before, but it's in control and I think I can be of a lot of help in the hunts. Sammy doesn't even need to do anything. And any big bad that wants to take over Heaven or Hell or whatever — I can pretty much take anyone down. "

"Your brother would like to kill Metatron himself and when the time comes, you should let him do it."

Dean frowned. "Metatron isn't dead?"

"No, we need him. I have managed to imprison him, though."

"So you haven't learned from so many centuries of mistakes, huh."

Castiel narrowed his eyes and leaned forward. "I don't understand what you mean to say."

"Cas, it's always crap like this that manages to land us in deep shit. Someone screws up by being too kind or too stupid."

"I am not stupid, Dean."

"Are you sure?"

Castiel knew that Dean might not mean much of it, but he was hurt. He sat back. "We need Metatron to find out if there's a way to reopen the gates of Heaven. For the souls too. And," he added, "I am not cruel."

"Sure, you can say that now after having killed thousands of angels before, eh?" Dean said. "But hey," he cocked his eyebrows, "I get it. You don't want that to happen again."

Castiel clenched his jaw. "Are you deliberately trying to anger me?"

"No, I'm just stating the facts. Much like you and Sam have been doing all along this whole year. Neither of you seemed to think how I'd feel. Funny."

Castiel frowned. "I had nothing to do with any of that. If you recollect, I was there, Dean, for you, when you had track down Gadreel after he left the bunker."

I wanna talk about anything that isn't a demon sticking needles into my brother's brain.

"And then you left with Sam. If both of you were so worried about the Mark, you should have devised some other brilliant plan to kill Abaddon."

"Abaddon didn't need killing," Castiel snapped, feeling anger rise in him. It bothered him how much this wasn't Dean. He remembered the hurt from Dean suspecting he was behind the angel bombings, and Castiel felt it return, knowing that deep down, this was probably how Dean felt. Being a demon was removing his inhibitions and making him honest. Demons lied, but sometimes they were also brutally honest when they knew it would hurt someone.

Dean was deliberately hurting him. Why would he do that?

"Uh," Dean said, "yeah, she did need to be killed."

"No, Dean," said Castiel. "She wasn't your problem. She wasn't our problem. You just made Crowley's life easier, and Abaddon's death served no purpose."

"She killed my grandfather."

"You don't have to avenge everyone, Dean. When she wasn't coming in your way, you should have let her go. And Crowley's company proved most detrimental to you."

"Do you want me to remind you why I was in his company in the first place?"

Castiel gripped the edges of the table. "Sam was sick and upset when you went off on your own. Would you rather I left him alone? He's my friend, Dean. I feel loyal towards both you and Sam. Unlike what Crowley feels for you."

"And guess what?" Dean said, "He made a better friend that both you fuckers. And I will gut him and kill him some day, but screw you."

"Yes, and I'm sure what he did was purely selfless." Castiel paused, taking a deep breath. "He knew about this and he always wanted it to happen, Dean. He wants to include you in his minions and train you. Have you considered that?"

"He ain't getting me," Dean said. "So you and Sammy can stop getting your panties in a bunch."

"Crowley is the least of our worries right now."

"Then get a hobby," Dean said, standing up to leave again. "Because I don't need either of you suddenly caring for me. I lived with it as a human, I'll live with it as a demon too. You two can bite me." When Dean left the room after that, Castiel felt worse for his friend than himself, because he hadn't realised the magnitude of pain that Dean had experienced from his and Sam's absence when he needed them.

Castiel felt sick. Dean hadn't been demonised by a mark or a blade or Cain or Crowley. No. It was him and Sam who had done it. It was them who had caused this. He thought back about the last year and wondered how many things he'd do differently if he knew that it would come to this. And he realised, he'd change a lot of things. Maybe he should have just spoken to Dean. If only Dean knew what he meant to Castiel, things would have been different. But things were not good, and now, Castiel would have to live with this guilt, which was his own doing.

~o~

Metatron sat in the darkness of his cell, watching the angel figure lean against the wall outside, watching him, silhouetted in the light. He curled his fists in anger. He couldn't believe that after all his plotting and planning, Castiel had ultimately written a better story than he had. And with a dead romantic hero too.

However, all metaphors aside, Metatron had thought that eliminating Dean Winchester would solve the problem. He had expected Castiel to put up a futile fight and go out, and hoped that Sam Winchester would finally kill himself out of grief or something. And even if he didn't, Metatron would have found him and killed him anyway.

All his plans had been thwarted.

He glanced at the figure still watching him, one of Castiel's minions, no doubt. He crossed his arms across his chest and huffed at the angel. "Stop staring, will you?"

"I am here to keep an eye on you," came the reply.

"And it's like I can go somewhere," Metatron replied exasperatedly.

"I don't trust you. None of us trust you anymore."

Metatron snorted. "Bad choice. Since I'm the only one who can for-real reopen the gates of Heaven. Without any need for that portal. And with a spell that will ensure everybody gets their beloved wings back. But hey," he raised his hands in a surrendering gesture, "I get you all. Keep me here. It's obviously the best punishment for trying to bring back order in Heaven. And as an added treat, you can all watch Castiel rot over losing the love of his life. I'm sure that's more important to you than your wings. Or your original strengths. Or the fact that you can be real angels again."

The other angel didn't reply.

"I know you think I'm lying," Metatron said dully. He suddenly had a plan. A desperate plan that might not work, but right now, he needed anything that might get him out of here. "And, you know, I might be lying too. You can't really test the theory now, can you? But you should think of what you might be letting go of, in case I'm telling you the truth."

"You can say whatever you want," the guard replied, "but we won't believe you."

"Yeah," Metatron sighed, "I know." He waved his hand. "It's okay. I'm a real angel anyway. I have my wings and everything. This… prison doesn't bother me so much, since I have hundreds of stories that I can go back and read in my head. And that's really quite entertaining — you'd know if you liked a book here and a tome there… some light stuff and then some dark. If you want to be you again, though…"

"I would suggest that you keep quiet," the angel across him snapped in a slightly hesitant voice.

Metatron knew, at that instant, that he had hit his target. He faked a yawn. "Sorry," he said, "I get bored." And then he sank into the shadows, hoping against hope again, that his plan would work.

~o~

Dean couldn't sleep. Of course, he was a demon, and he didn't need to sleep, and his body didn't need it, but right now, he wished he could switch off just for some time.

A few minutes after his talk with Castiel, Dean had felt like something had changed in him, opened some previously-clogged part of his brain and he'd recollected his conversation, cringing at whatever he'd said to Cas. And then he remembered the jab he'd made at Sam and it made him feel worse.

He honestly hadn't meant any of that. It had been like another part of him had woken up to say all that. A part of his hurt, angry self from before, which seemingly hadn't existed ever since his transition into a demon. But he was wrong. That portion of him had just been twisted, and even though he had really been angry at Sam and Cas at different points in his life, he wasn't now, and he didn't like that it came out life this, just to hurt them.

Dean ran a hand down his face and got up from his bed. The sheets were blood-stained, and they didn't bother Dean, but he knew Sam wouldn't like them like that, and he decided to change them soon. Now, though, he had some stuff to do.

He made his way down the hallway, to Sam's room. It was very late at night, nearing dawn, now, and Dean knew that Sam had left to sleep, but he also knew that Sam wasn't sleeping. There was no way Sam was sleepy, with his cogwheels whirring away at everything that had transpired, and the whole fact that Dean was a demon. Sam was too thoughtful to let go of consciousness that easily.

The door was shut all the way and Dean couldn't see light seeping out from beneath the crack, but he knocked. There was no answer. Dean put his ear to the thick wood and listened for movements, but couldn't hear any.

Maybe Sam was really asleep?

Somehow, Dean doubted that. He knocked again. This time, though, a tired voice answered him. "Come in."

Dean pushed the door open slowly to see Sam sitting up on his bed, brushing his hair out of his eyes. When he saw Dean, though, he stiffened, although he didn't reach for the angel blade on his bedside table. There was awkward silence, stretching for several moments. And then –

"Hey," said Sam, warily.

"Not sleeping?" Dean asked him, shutting the door behind him, so that Sam stiffened more. Dean raised his hands in surrender. "I won't hurt you, okay?"

Sam nodded, but didn't relax. He snorted. "Would you sleep?"

"I apparently don't need to anymore."

"Yeah, I figured," said Sam, turning away from Dean.

Dean hesitated, just for a moment, before making his way to Sam's bed. He sat down tentatively, and was relieved, when Sam didn't flinch away or something. He looked up at his brother. "Hey, listen, about what I said before—"

Sam nodded frantically, not quite meeting eyes with Dean. "Yeah, I know. You're right. We don't want you infected."

"No, listen to me," said Dean. "I didn't mean it like that."

"Sure." Sam was still nodding a lot and Dean felt frustrated. He suddenly had the urge to grab his brother by his shoulders and shake him, but he didn't do that. Instead, he sighed.

"I meant to say — we'll have to find a way to get rid of the Mark first. Because I might not get cured otherwise."

"Okay," Sam replied meekly.

"Sam—"

"Yeah, yeah," he looked up. "Uh… I'll research, okay? Whatever you want. Maybe—"

"Sam, I'm not trying to order you around," said Dean calmly. "I'm not going to hurt you if you don't do what I say."

"I know," Sam replied, and he sounded so small and… fuck. Dean knew that tone.

"Sammy," said Dean as softly as he could, and was surprised at the wetness in his brother's eyes when they finally met gazes.

"Yeah," Sam said in a broken voice, trying to hide his face from Dean again. "I know you won't hurt me. And even if you do, God know, I deserve it. I just… I wished I could have you back in a different way, you know?" He looked down and his hair fell into his eyes as he sniffed.

So Dean did the one thing he could think of, and actually hope to accomplish at that moment. He pulled his brother into a hug.

Sam seemed surprised, and he was wary for a while, before his arms came up to close around Dean. He heard another sniff and hugged his little brother tighter. "I know, kid. I wish it could be different too."

"Not a kid," said Sam, all but pouting in Dean's arms, and making him chuckle.

"You don't change one bit, do you?"

"I won't if you won't." It wasn't said as a joke, or in the light tone that Dean had just used, and Dean realised what Sam meant.

He sighed, remembering Crowley's words. "I won't, Sammy. I promise."

He just hoped that he wouldn't be taking back his words some day. And he imagined holding Sam just like this, with Sam bleeding and dead, and vowed to himself, to fight it all. Because he would never, in a million years, hurt his little brother.

A/N: Reviews? :D