I think this definitely sounds clearer and more focused, well done. You sound like you understand your own book, because you have described it clearly in para 1.
Couple of thoughts for the blurb bit (the bit we want to “zing”) – given that the book centres around the manananggal, I am curious to know how Galina becomes possessed… Could you put in an initial sentence to set this up? Currently it reads that Galina “just so happens” to be possessed – on other words, her possession serves only as a backdrop to the story, rather than as an active plot-point. Can you give us some kind of insight into how the possession took place? Can you make a hook out of that too?
Also – “There she meets…” This phrases lack conflict or drama. Can you “zing” this up?
The last line of your blurb is nice and zing-y: it has conflict and a sense of rising tension built into it, due to the juxtaposition of the protagonist(s)’s motivation (attraction to Galina) and key obstacle (increasing obsession).
I think your letter is working pretty well overall. What do you reckon?