I must admit, as a pretty staunch atheist I had real doubts at the start of the season when Cas appeared. I wasn't sure what to expect, and Dean's agnosticism had always appealed to me. I was worried he'd suddenly have a miraculous conversion.

I needn't have been worried though: the way it's playing out is much more interesting, especially if you consider Anna as an agent of the unknowable workings of God.