I thought of Castiel when I heard this song on the radio and thought it fitted his character beautifully. This is just a one shot but I really enjoyed exploring Castiel's character, I think he is awesome (almost definitely my favourite character on the show) and I can't wait to write more. Lyrics taken from the song 'Behind Blue Eyes' by the Who. I don't own Supernatural or the Who... haha. Hope you like :)

Behind Blue Eyes

No one knows what it's like to be the bad man, to be the sad man behind blue eyes

It had been a very long time since he had looked at his own reflection. He didn't really think about his appearance very much – he had a general idea of the way his vessel looked but he hadn't really had a very close look at the finer detail. More to the point, he hadn't ever placed great importance on the matter before now. It had never even occurred to him to examine his body.

He stared at himself in the mirror of the bathroom of Bobby's house, where he had been to look through Sam's laptop and Dean's notebook, trying to figure out what each of them was thinking. Looking at Dean's scrawling handwriting made him think of the nickname Dean had given him which everybody else had picked up on – 'Cas'. It was a curious thing, to have a nickname. To have somebody befriend you and become so used to your presence that using more than one syllable became a chore. And Castiel found it endearing, he found it almost amusing.

No one knows what it's like to be hated, to be fated to telling only lies

But it didn't matter how special the name made him feel, because Castiel had to go on pretending his relationship with Dean was purely professional. He couldn't help but like the rough-edged, bad-mouthed man. But Castiel was torn because if he let himself grow too close to the man, he would be taken away from him and shunned by his brothers. So he had to be close to him by keeping his distance from Dean, his only real friend. It was a paradox.

And now that he was aware of the friendship he had with Dean, Castiel was curious as to what Dean saw when he looked at him. Because what he saw wasn't necessarily Castiel himself, it was man named Jimmy who liked to wear baggy coats and double-knot his laces.

But my dreams, they aren't as empty as my conscience seems to be

Castiel frowned as he leaned forward, looking in the mirror. He vaguely remembered Jimmy as having rather neat dark hair and a clean shaven face, but his hair was longer and stuck up in every direction. He reached up to touch the tufts of hair sticking up above his forehead, before his fingertips scraped over the bristly stubble on his jaw and chin. Castiel thought for a moment about shaving it, to neaten himself up, but he sort of liked the way it looked. It looked like Dean.

He stared at his eyes, and realised he didn't actually know what colour they were. He hadn't even bothered to check, really, when he had been circling the vessel at first. But now he was staring at his own reflection, and he could see the brilliant Neptune blue staring back at him, flecks of grey dotted throughout, a ring of dark blue outside the iris. He had to admit that there were many things wrong with humans – they were sloppy, lazy, arrogant and stupid. But their eyes were spectacular. Castiel wondered how God could imagine such colours.

I have hours, only lonely, my love is vengeance that's never free

Castiel knew it had been almost an hour since Dean had woken up and gone downstairs, and Sam was still locked in the panic room. Castiel didn't like the screaming and yelling coming from the panic room, even if it was muffled by the thick walls. It was somewhat unnerving to know that Sam was falling to pieces. Castiel was a little worried at his relief – relief that it wasn't Dean trapped in there, writhing in pain. He didn't know why he liked Dean better, perhaps because he didn't trust Sam nearly as much. Dean was reliable, even if he was angry and stubborn most of the time. He and Castiel were usually on the same page. Castiel could understand Dean's struggles, he knew why he was so hesitant to trust people, while Sam had blind faith.

No one knows what it's like to feel these feelings like I do, and I blame you

If there was one thing Castiel had learned in his time outside of Jimmy's body, it was that having blind faith was the only way he could survive. But he wished he could be like Dean. Reckless and rebellious. Sticking the middle finger up at the man, as Dean would say – even though Castiel wasn't entirely sure who 'the man' was or why a person would feel inclined to make a gesture like that. All Castiel knew was that he wanted to know why he had to do the things he was doing, wanted to understand why he had to do them. He wanted to see the bigger picture.

But Castiel had been punished for his prying, for being lazy with the rules, for acting like a human would. His new found disregard for authority had made him feel better about himself, but the pain that followed was enough to make him stop. But the emotions, even Castiel couldn't figure out how to make those go away. He hadn't felt emotions like these before, emotions like anger and impatience and loneliness.

No one bites back as hard on their anger, none of my pain and woe can show through

He came to the conclusion that because he had befriended Dean and learned more about the intricacy of human emotions, he wanted to know how it felt to be so raw, to be so full of colour and energy instead of being a puppet of God.

Castiel frowned, and he thought about the way he had lost his trust in God, but found trust in Dean. How curious, that he would rather put his faith in emotions than in logic. Perhaps he was jealous of people, jealous of their energy and life and free will, jealous of their strange rugged beauty and wonderful eye colours.

If I swallow anything evil, put your finger down my throat

The angel wondered what Dean thought of him. It started out as a little question mark in his mind and became a nagging, persistent curiosity until Castiel decided to satisfy it. He had some time to kill before he had to carry out his orders, and he couldn't possibly get in that much trouble for talking to Dean, could he? He would tell Zachariah that Dean wasn't a friend, he was simply an informant. Castiel shifted, finding Dean sitting alone in the kitchen, flicking through a book as his eyes scanned the words on the page in an almost frenzied way. Castiel frowned as he watched the man researching haphazardly, and a moment later he said, "If you are looking for a key word, you should try the index."

Dean jumped, startled as ever at Castiel's unannounced entrance. "Jesus Christ!"

Castiel frowned. "Even if that wasn't already highly unlikely, why would Jesus Christ appear in Robert Singer's kitchen?"

Castiel could see the man try to regain his composure as he shot the angel an annoyed glance. "It's a figure of speech, Cas, I know you're not Jesus." The angel blinked at the nickname before Dean shut the heavy book and went on, saying, "So what's going on? I thought you weren't interested in helping me anymore."

"I wanted to ask a question," Castiel said in his low voice as he wandered around the table and sat down a little awkwardly. He didn't usually sit when he was talking with Dean. He looked at the man, head tipped slightly to the side and he asked him, "I was thinking about the punishment I received for defying my father. I was punished not because I helped you, but because I had more faith in you and your decisions than in my father and his orders."

Castiel paused, trying to think of the right words to use as Dean waited impatiently for him to finish. Castiel knew Dean wanted to urge him on, tell him to get on with it, but he held his tongue. Castiel said, frowning, "I want you to tell me what you think of me."

If I shiver, please give me a blanket, keep me warm, let me wear your coat

A slightly confused expression crossed Dean's face. "What?"

"I'm asking you what you think of me," Castiel asked, voice calm and careful. "Not what you think of me when I'm carrying out orders, or what you think of this vessel. Just what you think of me, when I have exercised my free will."

Dean stared at the angel strangely, before he asked, "Why are you asking me this, Cas?"

"I'm curious," Castiel replied simply. "Because you are the only person who knows that side of me, and I am interested to know what you think."

There was a small pause, before Dean said, "Well I think you're weird." Castiel was a little unsure of what he meant by that – after all, Castiel was already an angel inhabiting a man's body, chasing this hunter around to stop the apocalypse. Being weird was bound to be a side effect. But then Castiel saw the smile tugging at Dean's lips and he realised he was being humorous.

Before Castiel could say anything, Dean was speaking again. "I think you're alright, Cas. I mean you've helped me more times than I can count, and you've always got my back. I trust you. And I think – you've had a taste of free will, and you want more. I admire that."

"You admire my dissent?"

"Any person can be a sheep, Cas," Dean said. "Following the crowd. Your brothers might be warriors of heaven, but it takes a true fighter to rebel and do what's right. You're the sheep who wants to know why you're going that way," Dean pointed to his left, "Instead of this way," he finished, pointing to his right.

Castiel frowned. "It's not so much the geographic location I'm worried about, I'm mostly concerned about the imminent apocalypse."

Dean rolled his eyes. "Yeah, it's a metaphor, Cas. But that's what I think. I think you're better because you're different."

Castiel stared into the dark green eyes of the rugged, unkempt, uncaring man sitting opposite him and he knew that he could trust Dean, that he could believe everything he said because he was brutally honest, he wasn't worried about Castiel's feelings, or lack thereof. Here was a man who knew Castiel better than his own father, than his own brothers in heaven.

He wondered again how God could create such colourful beings as he examined Dean's shining green eyes and he then said slowly, "Thank you, Dean. You are – a very good friend." He didn't bother saying goodbye, because he knew he'd be seeing him sooner than he thought.

Because it was in that moment Castiel decided he would disregard the orders. He was past caring about why, or how, or what – all he knew was that he and Dean shared a trust that Castiel had never known before or since, a trust that sported nicknames and metaphors but also blood and sweat and pain. Castiel felt like Dean was more of a brother to him than any other angel could be.

So yes, he would release Sam from the panic room. But Zachariah hadn't told him what to do after that, and Castiel decided he was going to do whatever was in his power to help Dean stop this apocalypse, and Castiel wanted to prove to Dean that he was better than the others. He could be better for his lowly, rusty human friend because nobody else knew him better. The angels saw him as a soldier, a puppet of the Lord, and humans saw him as a rather ordinary looking human man in a trenchcoat with alarmingly blue eyes, but Dean saw Castiel for who he was.

No one knows what it's like to be the bad man, to be the sad man behind blue eyes