LoneKonWolf
So to answer your questions...
"Why/What were the creatures chanting?"
Well that's the simplest answer I can give. As by the looks of it it's based on an ancient hymn made by some wolfen poet who's name I don't understand. Why? Well to worship the moon goddess most likely.
"What was that deity you saw and why?"
Well, you know that moon goddess you were telling me a while ago? Well, I'm assuming she has something to do with it.
For why, I think it's a symbolic representation of something. Could be wrong, but in some way this is a celebration of the works the moon brings, so Uni could represent the worship given to the goddess.
Apart from that, I have no clue about the crater or why it looked like the moon crashed. Magic moonbeams maybe?