A Journal, for Humanity (Supernatural)

Hello. My Name is Castiel. I am an Angel of the Lord. This is my journal. It was recommended that I keep one by Dean Winchester, a very good friend of mine, and a human.
Strange things are happening, some of which have happened before, some that I have never before seen.
I know now what I must do.
I must find my Father.
(This story is not deeply rooted in any particular time in the series, but I think you can guess approximately when events are taking place)