Supernatural and the characters are not mine,
this story is a one-shot but if there are enough people interested, I could make it longer and even write smut.
It's rated K+ for now but it could change depending of what you want it to become.
Once again, english isn't my native language so I'm sorry about any possible misspell or mistakes,
if you notice any, I'd be grateful if you told me :)
Anyway, enjoy! (And I'm sorry for the feels x))

"Cas... Dean is in trouble."

The angel remained silent at his friend's answer. The words were resounding in his head. He had known for a while that things were getting really bad but he only started realizing it now. Sam had always been so confident, hiding his fears from Dean to preserve him. He had always been the one repeating over and over again that they would find a way to fix everything and now, he was as panicked as Castiel was. A strange knot was twisting the blue eyed man's stomach and a strong feeling was growing inside of him. He understood it was pure anxiety when he noticed he had been holding his breath since Sam had talked. Castiel had never felt such helplessness or worry and he couldn't even mutter a single word to comfort Sam. He closed his eyes for a few seconds and took a deep breath in. How had things got so bad? How had they ended up here? The angel's legs were slightly shaking and he was feeling the urge to sit down. But he just couldn't allow himself to lament like this and be so weak, although the simple thought of possibly losing Dean and Sam was breaking his heart. He shook his head to clear up his ideas and turned heels on Sam who immediately asked him where he was going.
"I need some air." He answered as he had heard Dean do so many times.
The truth was, he could only think of one person who might be able to help them, even though asking for his assistance was a sin in itself. He was going to find Metatron and no matter what he would want from him in exchange of informations about the mark, he would give it to him.
However, as he was walking down the corridor, approaching Dean's room, he heard a weird noise. Instantly concerned, he got closer with caution. What he discovered wasn't near what he had anticipated. He froze on the threshold of the door, trying to make sense of what he was witnessing. Dean was seated on his bed, his face burried in his hands, a small sob was sometimes shaking his body. Castiel was unsure of what to do, or if he even had to do anything. Dean could reject him and not want his compassion. But the scene was ripping his heart in two and he decided it didn't matter if Dean took his concern for pity, he just couldn't leave him like that; he couldn't ignore the pain of the man who had done so much for him, who had always been here when he had needed it. Before he could step forward, the hunter raised his gaze and his eyes filled with surprise when he saw the angel. He hastened to rub his eyes, as if he didn't want Castiel to see him like this, hiding his suffering, holding back his tears once again. It somehow saddened the fallen angel that he wouldn't share his feelings and put up a mask to hide behind, even with him. He had thought that after all they had been through, they didn't have to pretend. He wasn't his brother, he didn't have to be strong for him, he could tell him everything. Even if this sight hurt Castiel, he wanted Dean to let go of all these feelings which had been suffocating him for so long.
"C-Cas?" He whispered. "What are you doing here?"
- "Weren't you supposed to get some rest, Dean?" The angel questionned.
The hunter let out a heavy sigh and let his head fall back in his hands, avoiding his gaze. Castiel knew he wasn't going to answer so he entered the room. Dean then deigned lift his eyes and followed closely his very movements as he sat beside him. A silence set up between the two of them. Castiel wanted to say something but his throat was tightened and his mouth felt dry. When he finally spoke, he used a far weaker voice than he had intended.
"Dean... Do you want to talk about it?"
The angel had lost every ounce of confidence he had had before facing him. He was afraid, not of Dean but for Dean. He didn't know if what he was doing was correct, but it felt right. He remembered the Winchester ordering the same thing of him, only less nicely. "Talk to me." That's what he had said and he had felt unable to disobey, it had felt like a relief to tell him everything. It had felt nice, because someone was caring. It seemed now normal to show Dean that he cared as well. And God knew how much he really cared about him.
- "I don't know... It's just... It's too much, Cas." Dean finally replied. "We're never getting out of this, there's no way it ends well and you know it. Caïn... The things he said... If it happens... I just don't know man."
His voice was broken and every single word left a burning scar on Castiel's heart. Dean's despair was beginning to expand to his. Thinking about it, he didn't see any way out either, or at least, not any good way. It didn't change the fact that what was the most unbearable to him right now was Dean's state. Moreover, he could finally see his face clearly now that he was looking straight at him. The dark haired man's stomach twisted when he noticed how sad and tired he looked. His skin was pale and his features were tensed, his usually full of life beautiful green eyes were puffy and full of tears instead. It didn't stop Castiel from finding him beautiful, even though he wouldn't admit it. His soul wasn't as pure as it used to be and it was clear that some parts of his being had been damaged to the point of no return but he was shining to the angel's eyes, after all, he had always been. He wished he could do something more, reassure him, tell him everything would be alright but he didn't feel strong enough to lie directly to him or to himself. He tried to push away the undeniable feeling the story was coming to an end but it looked like fatality was catching up on them. His eyes began to stung, as if tears were trying to find their way through his confused feelings and he realized he really much needed comfort too. His thoughts were cut short when Dean spoke again.
"He told me I would... Kill both you and Sam, even Crowley. I... I would never harm you... I'd rather die."
From the way he was looking at him, Castiel could tell he was looking for some kind of confirmation. He was waiting for the angel to lie this time, because that's what he needed right now. But he didn't have to lie.
- "Dean, you are not Caïn. You won't do the same mistakes because you are stronger than him, and you know what is supposed to happen. You'll make sure things don't go the way you don't want them to go."
- "No Cas, you don't get it." Dean breathed out, shaking his head. "He said I was living his life in reverse and that was how the story would end. First I'd kill Crowley, there would be some strange mixed feelings about this one but you'd have your reasons, you'd get it done, then you would kill the angel, Castiel. And this one, that I suspect would hurt something awful. Then would come the murder you'd never survive..." He stopped, out of breath.
Tears were slipping down the hunter's cheeks and Castiel's eyes were wide. The voice he had taken wasn't his and the words he had used wasn't his either. He wasn't staring at him anymore, he was fixing an imaginary point far behind him. The words must have marked him deeply because he remembered each one perfectly. He could even imitate Caïn's tragic tone while saying them.
Castiel only wanted one thing, for Dean to stop crying because he couldn't stand it. He didn't deserve to be put in so much pain without it possibly being removed.
The blue eyed angel desired proximity, contact, and he didn't know why. Those had never been elements he'd use to comfort himself, those were very human.
"There is no cure. There is no stopping, no escaping the mark." Dean repeated, echoing his own fears. "I'm not able to... I've always been afraid I'd lose my family, Cas. And I have but... I never thought I'd be scared of killing them. I..."
- "You won't." Castiel interrupted with a harsh voice. "I have never seen anyone as loyal to his family as you, Dean. It's always been so important to you, there is no way you'd harm us."
The hunter tried to look away, unable to hear what Castiel was saying but he forced him to be attentive.
"You listen to me, Dean. I gave everything, I sacrificed my brothers and sisters, I denied the existance of my father, and it was for a reason. It's because those are not what I chose to put my faith into. If I have faith in anything, it's you. I have lived for billions of years and yet I realized I didn't know anything before I met you, I wasn't aware of the important values of life before you. Don't ask me to believe in anything else than you, Dean. I don't believe in destiny, or fate, or even fatality. As long as we're together, I choose to believe that there is hope."
Everything he had just said, he had wanted to say it for a very long time and now, the pressure decreased a bit. The hunter was staring widely at him again, shocked, tears still dripping from his eyes. He opened his mouth and closed it instantly, as if he was about about to add something but had chosen not to. Then, he gently touched Castiel's cheek and observed the small drop of water he had picked with his finger. The angel was crying, and Dean had never seen him cry. Castiel had always forbidden himself to show his feelings, as the eldest Winchester always had. Now he felt like he would never be able to stop and a slight sob escaped his crackled lips.
- "Cas..." Dean breathed out, like a plaint.
He watched as the hunter closed his eyes tightly, trying to stop weeping himself. Castiel's speech was making him cry even more and the angel didn't know why, but he started to feel guilty about it.
- "Did I say something wrong?" He wondered, with a tone as broken as his grace.
- "No, Cas. You... Dammit."
He got closer to the angel and quietly took him in his arms, looking for nearness as well. Castiel decided not to think anymore and held him tight, clenching to him as if he was his only anchor to reality. The angel understood he wouldn't be able to see Dean disappear again, his worst scare was to lose him. He let out a tired sigh and murmured:
- "Dean, don't leave me, please... The angels aren't my family, you are, I need you. You and Sam are all I have, please don't take that away."
- "I don't know how to stop it but I can try... I don't want to lose you either, but I'm scared Cas and maybe it would be better if you and Sam... Stayed away for a while."
Castiel tensed immediately and affirmed firmly:
- "No. I won't Dean and you won't make me. I will not leave you, I will find a way. I promise, I will. No matter what are the costs, I will make sure we make it. I'd do anything, I swear, please... don't..."
He ceased talking, overwhelmed by a thousand of different emotions. He needed to pull himself together, Dean's shoulder was wet of his tears. And he knew Dean wasn't in a better shape. He could sense something, some kind of tension floating above them, as if there was something they needed to say but weren't quite brave enough to formulate. Castiel was trying his best to make him understand by other ways but he wouldn't be able to keep it in much longer.
- "Cas, calm down..." Dean soothed. "It's only for a few weeks, so I won't put you in danger because... You know I wouldn't be able to live with myself if I even laid a hand on you."
The angel frowned, wondering for a second why Dean was so uncomfortable with the idea of laying a hand on him as they were still hugging but he quickly understood he didn't mean it literally.
- "You won't, I know you won't. How many times did people say you would hurt or kill the ones you love? How many times did you actually save their lives instead?"
Dean didn't have anything to answer, because it was true.
- "Thank you, Cas. Thank you for always being here." He said, with true thankfulness in his voice. "I will never understand why you are so nice to us, to me. But I am so grateful I have you."
- "Because you are important to me, Dean, more than any human word could express." The angel replied without hesitation. "Because..."
The hunter grabbed his shoulders and pulled away from the hug, looking into his eyes. There was sadness in Dean's gaze but there was hope, too. He had stopped crying.
- "Because what Cas?"
Castiel looked down, slightly blushing. He had to say it now. The tension between them was caused by three little words. He didn't know how he was going to react, he wasn't able to understand human's feelings well enough to predict what would come out of this, but he decided he didn't care. Dean deserved to know, needed to know. He swallowed, pushing his pride away, lifting his head so he was facing the Winchester again.
- "Because I love you, Dean."
He had learned there wasn't anything else needed for that. He didn't have to add anything, it couldn't be clearer. His words lighted up something in Dean's eyes and he could almost see the shadow of a smirk drawing on his lips. He kept on staring at him without saying anything, he didn't look angry or anything so Castiel relaxed a bit.
"You're not mad?" He questionned.
The hunter closed his eyes and sighed.
- "No, no I'm not. Stupid angel..."
No matter how he turned those words, he couldn't understand why they sounded so lovingly. This time, Castiel was the one reaching out for him, pulling him close. He had the feeling Dean had known for a while, judging by his reaction. The confirmation seemed to have pleased him, though. He realized he hadn't opened his eyes since he had talked and he was breathing slowly, almost peacefully. Castiel couldn't help but smile at the sight, knowing he was falling asleep while still being seated. With as much softness as he could, the angel lied him down. He stayed a few minutes, just watching him, contemplating his appeased features, listening to the regular beatings of his heart. Deciding he needed rest, he started getting up but a hand gripped his.
"Stay, please." Dean asked, eyes half opened.
He pulled him and Castiel settled next to him. Lying on his side so he could face him, Dean seemed completely awake now. Castiel adopted the same position so he could be facing him too. The green eyed man still hadn't let go of his hand. Something in Dean's eyes was still off, and he knew he was still worried every time he thought about Caïn's words but it was better. It was only a start, but it was better.
"Cas, did you hear about Caïn's story?" Dean said. "About Colette?"
The angel nodded, even though he didn't know why he was mentioning this now.
"She kept him from the blade, she made him stop. He fought it, thanks to her. She was the love of his life."
Castiel felt even more confused but he didn't say anything, not wanting to interrupt.
"I think Caïn knew from the beginning, as soon as he saw me. Because he knew what words to use, he knew what hurts."
- "What did he know, Dean?"
- "Before... All this, I had other concerns." The hunter responded. "I didn't realize how dumb they were but now I can see it clearly."
The angel frowned, lost. He didn't understand where this was going.
"See, I didn't want to truly let someone in, because I didn't want to hurt them. There was something I was ignoring, something I tried not to think about. Something I denied for years because I was scared and stupid."
- "You are not stupid, Dean." Castiel assured.
- "Yeah, right." He chuckled. "Well anyway, now I know it's not wrong or anything, because it makes me happy. I'm gonna tell you something I never said to anyone, Cas."
- "I am listening." The angel muttered, attentive.
- "I love you too. And I really don't care what anyone has to say about this anymore."A warm sensation filled Castiel's heart and he couldn't describe the relief and happiness those words were rising within. He understood now what Dean had meant when he had brought Caïn and Colette in the conversation. He had been comparing him to Caïn's love and that was making him very content.
"Cas don't cry!" Dean ordered and the angel didn't get why until he felt a tear falling on his cheek.
The Winchester wiped it away and softly put his lips on his. Closing his eyes, Castiel kissed him back, savoring the sweetness of the situation, of finally being able to do what he had waited for so long. This kiss had the taste of hope and tears, but it was definitely the best thing Castiel had ever experienced for now. When they pulled away, both of them being out of breath, Dean was still cupping the blue eyed man's cheek with one hand, holding him with the other. They stayed incredibly close, breathing each other's air, enjoying the simple fact of being together. Castiel changed their hands's position so their fingers would be entwined. Dean was kindly stroking Castiel's hair with his free hand, closing his eyes. His face was showing so much peace, he had finally said what he had been keeping in for such a long time and he had one less thing to worry about. The angel now had to make sure he didn't have to worry about anything else. He was going to fix this. There wasn't a single thing he wouldn't do for Dean, he honestly couldn't even think of one. Nothing would stop him for finally granting his hunter the hapiness he deserved. He kissed Dean's forehead, promising to his inner self he would watch over him. The young man leaned in and burried his head in the hollow of Castiel's shoulder. After a few minutes, the angel could tell by Dean's quiet breath that he was asleep, for good. His own eyes were closing themselves and because he was more human than he had ever been, he felt tiredness catching up on him. He fell asleep as well, his chin still resting on Dean's head. Whatever was coming, they would deal with it. They had each other and right now, that was all that mattered.

Later during the night, Sam would come to Dean's room to check on his brother and make sure he was really taking the rest he needed. He would find the door open already and see Castiel in the bed with his brother, their bodies perfectly nested against each other. They would both be asleep, at peace, more than Sam had never seen them. The younger Winchester would smile without surprise, not that he had expected anything like that, but he had known the strength of the feelings they had had for each other since he had first noticed the stares and the way his brother acted when Castiel was around. He would slowly close the door and mutter to himself with a smirk still on his lips:
- "I said it, Destiel."

Could you please tell me what you thought about it? It really means a lot to me, thank you! Don't forget to post a review :3