Oh, you're talking about that one author, what's his name. I'm know the series you're talking about. This author's theory is to be rejected on two accounts. I've studied some of it and won't name any references though (because I can't think of them off the top of my head).
First, he gets the language wrong, which seems to basically falsify his whole theory. He equates the nephilim with the anunnaki. There probably IS a connection though since the nephilim are black, according to Numbers, and the Anunnaki are of the Sumerians and so black in that regard too. Yet the language is wrong. For example, the term "nephilim" is actually an Aramaic loan word used in the Hebrew according to Michael Heiser. You can tell because there are actually two forms of the Hebraic nephilim found in Gen. 6:4 and Numbers (forget the chapter, look it up - possibly 30 or 31). The two different forms gives it away as an Aramaic loan word, which in the Aramaic simply means "giants". So the English translation of "giants" is quite apt. It doesn't mean "gods", "alien", or "angels". It's simply means "giants". And yet Numbers gave a retrospective where we understand these to have been black giants. The Philistines, for example, were likely black, so Goliath was black. If they weren't, the Philistines were still an intermixed breed. The earliest Egyptians were also of the Nephilim race: the earliest skeletons show taller bodies and a more elongated skull (and um, no, this doesn't mean "alien", it probably means some level of inbreeding).
Sorry, that was long winded. Second, physical evidence from the moon, mentioned from a book I don't recall but have in my possession, shows that the moon could not have come from the influence of some "Planet X", what's it's name - something like Nibiru (I forget, it's been a couple years).
So...no, aliens didn't come from a Planet X to interbreed with humans; neither did spirit-angels (as if spirits have DNA!). If there's any link between the Anunnaki and the Nephilim, it's the fact that the nephilim were black giants. As a side note, other myths across the world explain the three main reasons for Noah's flood: 1) they reveled in pleasure, described in the phrase "eat, drink, and be marry, for tomorrow we die", 2) they were violent - evident in the phrase "tomorrow we die", and 3) they were into cannabalism, which is ultimately where our myths of legends of vampires and werewolves come from (it doesn't originate with Vlad). The Sumerians had the, oh I forget the term, Ennib - bah, I forget! But this was basically a soul sucker, a spirit of the dead that ate the living. It's actually a merging of two myths: the myth that dead spirits rise, and the myth that had to do with Cannabalism. I came across this information in the "Ashes of Angels" book. It talks about how these vampires were giants. The Book of Enoch gives like evidence - they began to eat each other. And the other myth comes from the ancient Greek myth where Zeus destroyed the world because human's began to think of themselves as wolves, perhaps wearing wolf clothes and the like but basically eating human flesh - something like that. The myths of the vampires and werewolves are connected and basically one and the same. In short, the world was destroyed for: 1) lustful pleasures, 2) violence, 3) cannabalism...and...actually a fourth reason. The nephilim began to corrupt the proto-temple ceremonies, and you know what starts to happen when people mess with temple things. Take the Ark of the Covenant - touch it unworthily and you die, so as to avoid corruption. How do I know this? That, my friend, is for another discussion. If anyone posts on the main thread catching my attention by using "Patrick" in the title, I will discuss what I know. (In the end, it's actually quite simple. No one ever gets it right though - all scholars alike - because no one ever studies the Jewish temple.)
So the four reasons again: 1) lustful pleasures before war, 2) violence, 3) cannabalism to the victors, 4) some connection to the proto-temples.
But...the earth wasn't destroyed because of a bunch of aliens, who btw weren't even smart enough to do their own mining!!! I mean, come on? If you have all this technology and intelligence, you certainly don't need primitive slaves.
(That remains me, there was some Sumerian myth about a pickax. I forget what I concluded on that. But the pickax actually was a term for "falling star". Some sort of catastrophe is most evident - "extraterrestrial" if you like, but not as in "alien". It might be connected to the flood. I forget. Would probably have to read the myth again but am too lazy.)
