You know, I like these guys. But it feels incomplete somehow. I would like to know more of their background, where they come from, what their plans are etc. How big are they? What equipment do they use? How do they communicate?
You mention "Host Bodies". Does that mean they evolve as some form of parasite? Are they true extraterrestrials, some form of hybrid or a runaway bioengineering experiment?
So many questions.... To vote now not give this idea justice - I will wait :)
I have to say, I like this more and more. I take it you draw heavily from the CoC. Also a quite nice sideorder of Demon, the Fallen, unless I am mistaken? Thank you for taking time to answer :)
I think this has great potential. There is obviously a systematic framework in place. I do like that, it reminds me of the Cthulhu Mythos, allowing for additions as you go along.
Have you read John Keel´s "Creatures from time and space"? It describes very much the same phenomenon as an explanation for Bigfoot, the Loch Ness monster, Mothman and so on. If you haven´t read it, I think you can get some good inspirations there.