Pay careful attention to what Watchman Nee said. He said the union of spirits with men to create the Nephilim was not from the 1/3 of the angels that fell with Lucifer, but was outside that angelic host, so it would be of course the disembodied spirits, the demons, instead.

Nee calls the spirit that entered the serpent a Satanic spirit, not that the spirit was Satan. It's like saying when Jesus died around 30 AD so that He didn't die in 30 AD but somewhere about then around 27 to 33 AD.

Satan can't himself enter people, all he can do is plant suggestions and ideas, but demons because they were part of the former world can inhabit bodies - hence the term, demonic possession NOT angelic possession. It was a demon who is a Satanic spirit that entered the serpent to tempt Eve under the instruction of Satan of course.

So it is not the fallen angels that had sex because they can't do that. Spirit beings can't have sex with physical beings. Demons can't have sex either. But what they can do is possess the body of a human if the person allows them entrance and when that human being has sex a strange genetic aberration takes place which created the Nephilim.

Thank you Lord for this discernment. Amen.