Hmm, interesting question. The Lunatic Pandora (lunatic meaning 'coming from the moon or having a relation with it in one way') attracts monsters from the moon, and Sorceresses appear to have a special connection with it.

My own pet-speculation? Hyne's up there, watching the humans that once defeated him and trying to push them down by destroying their most advanced countries in a sea of monstes. (link with the sorceress? Sorceress power IS the power of Hyne, the half that humanity stole)

Of course, another reason is that the moon is just really, really cool to show at dramatic moments.

Oh yes, a friendly hint... MAKE THE SIG SMALLER. Really, it'll be a tad irritating when people have to scroll through your life story for every single post.