'Father…? This is Castiel. No one may be listening, but I need your help. I wouldn't be asking for it if I knew how to… keep things straight. I know that you have left heaven… have left us long ago. But… I am desperate.
As you certainly know, Metatron took my grace. It was one of the ingredients he needed for the spell he wanted to perform. In order to shut heaven down, what led to our fall. I saw how my brothers and sisters were banished and couldn't do anything about it, in first place. It was the most… terrifying thing I have ever witnessed in my whole life.
In my distress, however, I took another angels' grace to help my siblings with taking Metatron down or, at least, imprisoning him.
But it's not my grace, and it's slowly burning out. And when it's gone, I will die. Metatron told me, that there was enough of my own grace left over from the spell when I went to see him in heavens' dungeon. He also assured me, that he would give it to me if I let him out. But I can't trust him. How could I, after the horrible things he has done? He's a liar.
Currently, my brothers and sisters experience what you might call 'free will'. At the moment, there is no such thing as a 'leader' of heaven. Some don't accept that. Just like Metatron or Naomi. Or even me, a few years ago. Now I do.
Angels are slaughtering each other and I can't bear that anymore. I need to help them, but I don't long for leadership. I am no leader.
There is still so much left to do for me here on earth and up there in heaven. I have to clean up the mess Metatron has made. Many wanted him dead, after all.
What is this, though? What kind of world do we live in, in which even angels deserve to die? And I will die, father.
I am not willing to kill a brother or sister of mine and take their grace again. That would be wrong, yes, it would be unforgivable. And I have made enough mistakes, I have done enough unforgivable things, for a lifetime and further.
I told Metatron that I had accepted the fact that I'd die for certain, that I had made peace with… everything. But that's not the truth.
The truth is, that I can't let go. I can't let go of this world, no matter how screwed up it might be. And I can't let go of my brothers and sisters. I can't let go of Dean Winchester, I fell for him in every possible way. And I certainly can't let go of humanity itself since I've been human myself for some time. And now I'm about to die, father. I'm not saying I didn't deserve to, but I simply don't want to.
… I just want to be an angel.'