Dear Dean,

If you are reading this, it means that I have finally passed from this universe. I am dead, definitively, completely, and with no possibility of returning. I know it seems hard to believe, that in our world anyone can truly pass beyond mortal reach. It seems there's always a way to find someone again, via Heaven or Hell or even ghosthood. But, with angels it's different. I know I have appeared to die before, and have returned to you from beyond the grave, but this time I don't think any such thing will happen. This time, I'm gone for good. And I'm sorry, but the very fact that you're reading this letter means that I can't be coming back.

At the time I'm writing this, I don't know the circumstances surrounding my death. If we parted on friendly terms, then that is well and good. If we had some sort of falling out before I left, then this is my opportunity to apologize. I hope you can forgive me enough to continue reading. Despite anything I may have said or done, I always have and always will have nothing but good will towards you Dean. I simply could not harbor anything else.

To tell you the absolute truth, I feel I must inform you that the moment I raised you from Hell was not the first moment we had met. I have known you for far longer than that. Here, in this letter, I wish to tell you the full story, as I doubt I will ever be able to get it out while I am still alive. There are some things that I don't have the courage to say aloud, no matter how badly I want you to know. So, let me write it here, and I hope you can forgive me for my silence in this matter.

I first laid eyes on you during your very creation. I am not speaking of your conception by your parents – I am not partial to spying on fornicating humans. I am speaking of those few moments when God himself assembled you on His workbench, long before man had even said his first words. You were designed many thousands of years prior to any of your companions. I think now that God was planning the Apocalypse even then, and taking special time to make sure His Righteous Man was everything the world needed him to be. At the time though, I didn't know this. I didn't even know why God allowed me into His workshop that day.

"Castiel," he said, addressing me alone for the first and only time. "Come here. I want you to take a good, long look at this son."

I climbed up onto the table and obeyed, but I was not prepared for the sight before me. When I looked down at your pure self, laid out for assembly, I was awestruck. I had caught glimpses of my father's other creations before, but this was altogether different. You were magnificent, Dean. To this day I have seen nothing more beautiful than that first vision of you, and as my father bade me, I memorized every detail. I remember asking, "Who is he?"

God ignored my question. "Have you looked?" he asked. I nodded. "Good. Make sure you don't forget, Castiel. And for goodness' sake, you keep an eye on him all right?"

I nodded again, and He bade me go away and let Him finish His work. From that day I was assigned to watch over the humans, serving in one of many garrisons stationed on Earth. I spent long years watching, guarding, doing as I was told, but that held no satisfaction for me. Someday, I knew you would enter your mortal life on Earth, and it was for that day I waited.

I waited for thousands of years, always alert; looking ahead to the moment we would meet again. I was so sure I would know the moment you came into the world. Father would tell me, I told myself. He wanted me to look after you, after all. I would wait as long as was required, and the instant you exited your mother's womb, I would be there. It was destiny.

Imagine my surprise when Balthazar found you first.

He came to me in a hurry one day, completely unannounced. "Cas," he said, flashing into visibility. "You need to go to Lawrence, Kansas. Now."

"Why?" I asked him, confused.

He refused to meet my gaze. "It's…well…I shouldn't even be telling you," he said hastily. "But it's…you know. Him."

My heart plummeted. "What? He's here?" I asked.

Balthazar nodded. "Yeah. And…he's got company."

"What do you mean?" My tone was harsh.

"Well it's rather funny really. You'll never guess who his brother is."

Anger rose in my chest, and I stepped up to Balthazar. "He already has a brother?" I snapped. "How old is he? Why wasn't I told?"

"I don't know Cas! I only just found him myself, and it was completely an accident. I was on the Azazel case when I found out."

"What? But Azazel has nothing to do…" The realization hit me like a train. Without even finishing my sentence I vanished from in front of Balthazar.

I reappeared in front of your house just in time to see flames explode from within Sam's nursery. Seconds later, you pelted from the front door. I saw your face, the terror and desperation, the death grip you had on your little brother as you raced across the lawn. But, I am ashamed to say that what struck me the most was how old you already were. When the firelight lit upon your face, it was clear to me that you were at least four years old, and no one had told me. I, your chosen guardian, was not even told of your existence. I had waited for years, and if Balthazar hadn't stumbled across you, I would never even have known you existed.

Before you saw me, I was already on my way to Heaven, filled with wrath. I tried to find my Father, but he would not see me. Instead I ended up in a long argument with Michael over the matter, and he told me that you were his vessel and therefore none of my business. I was ordered back to my post, but I put my Father's orders above Michael's. I snuck away when I could, back to keep an eye on you. I couldn't interfere with your life in anyway, lest Michael found out, but I did the best I could.

As you know, the whole Azazel business made demons a much larger problem than they had any right to be, and I was consequently busy for a long while. I tried to keep up with what you and Sam were doing, but every move you made wrapped you further and further into the building chaos. You nearly died so many times…I thought Michael didn't even care about you then. But every time I tried to help, he was always there to send me away. "For the last time Castiel," he'd shout, "Dean Winchester is not your responsibility!" And I'd go away, back to whatever meaningless station they'd made up for me, but my thoughts were constantly with you.

Lilith arose from the ashes of Azazel's failed plans, and I knew that soon, seals would begin to break. My fears were confirmed when I heard of your deal with the crossroads demon for your brother's return to life. Destiny was closing in on all of us, and the Apocalypse was coming. The air in Heaven changed; the archangels seemed excited. I was caught up in the military effort to keep the seals from breaking, and so I didn't have time to think about it much, but now I realize how wrong it all was. I should have been able to see what was coming. But, at the time all I wanted was to stop the cage from opening, as I believed everyone else did.

I wanted more than anything to somehow keep you from Hell, but in the end, no one listened to me. The news came that the hellhounds had dragged you off. Immediately, all of Heaven went up in arms to break you out, and I was at the forefront of the charge. We laid siege to Hell, with all the might we could muster. I laid it upon myself to fight my way to you before Alastair tortured you into demonhood. To this day it still pains me when I think back on the moment we broke in, and discovered that we were too late. I was supposed to watch over you. It was the only order that God had ever given me, and yet when it really mattered, when it was up to me to get you out of Hell…I failed you, Dean. I was too slow. And when I laid my hand on you, and felt how broken you were, you turned and looked at me with such loathing that I was rendered speechless and immobile. One of my companions pulled us both away.

In that moment, all I could think of was that first time I had seen you on my father's table, how beautiful you were. This thing that I now held in my hands was hardly that; it was twisted, mean, and in pieces. My father's greatest work, dashed to bits in Hell because of my incompetence. I sat there for a great while, long after the other angels had given up and returned to Heaven, cradling your broken self in my arms and hating everything I had ever done. I hated that I had missed the moment of your birth. I hated that I had not spent every second by your side, protecting you from the world's ills. I hated that I had not been there to stop you from making the deal, or to put down Lilith, or to smite down every last monster that tried to cut your throat. In that moment, I was a failure.

It took some time, but eventually I was able to put you back together. The result was not perfect, but I could not hope to remake my father's work exactly. Instead I did the best I could, and then put you in your body again and left you to find your way out. Shortly thereafter I received permission from Heaven to begin direct intervention. I was officially assigned to your case, and so could finally stand by your side, as I had always wanted to.

You know the rest of the story. I still have not forgiven myself for my initial naivety on Earth, namely my attempt to emulate God. I know what you would say. "Come on Cas, that was years ago. We all make mistakes, even angels. Now let's go kill ourselves another demon." Part of me knows that you are right, but it is not strong enough to overcome my conscience. Nevertheless, since then we have had many long years of hunting together, and for those I am grateful. Even if many of those years were less than kind to us.

At the time I'm writing this, the last time I saw you was barely an hour ago. You were sitting out on the end of the dock at the safe house in Montana, fishing and drinking a beer. I suppose you are still there now, lounging in that folding chair, fishing rod in hand, watching the surface of the lake. I imagine the sun is starting to set, turning the sky and the water to the same shade of golden-pink. When I'm finished writing I'll go out there, ask you if you've caught anything, and you'll grin and say "yep" and proudly reach down to open the icebox full of trout. It's times like that that make the ordeal of falling from Heaven worth it. Since the day I finally did it, I haven't regretted it for a second. At this point I can safely say that it was the best decision I've ever made.

I know what little patience you have for reading, so I'll bring things to a close. I expect, as a fallen angel, I'll end up with all the rest of the humans upon my death. If so, I'll be waiting for you there. Try not to come along too soon - live a long and fulfilling life, with plenty of beer and road trips and women and whatever else it is that you do when I'm not around. I'll be there at the end, no matter how long I have to wait. I'm quite used to waiting for you Dean – I waited thousands of years on Earth for you to be born, and you know what? I could easily wait several thousand more, if that was what it took. I care about you more than anything else in the universe. You are still the most wonderful being I've ever seen, and someday I might have the courage to say that to your face. But for now, I will leave my affections written here.

This is my final secret. I love you, Dean. I always have, and always will. I don't know if you feel the same way, or even if you can, seeing as my vessel was male for all those years. Even so, now that I am dead it is no use hiding it. I do not know the nature of your feelings towards me, but now you know mine, and that is enough. I hope you will take them well.

Until we meet again,

- Cas

Dear Cas,

I'm coming you son of a bitch.

Love,

Dean