The Book of Enoch describes the fall of the Watchers, the angels who fathered the Nephilim/Nefilim. For those of you who do not know, The Smithsonian museum was ordered to destroy their bones of Giants/Nefilim.
In the Book of Enoch, the watchers are angels dispatched to Earth to watch over the humans. They soon begin to lust for human women and, at the prodding of their leader Samyaza, defect to illicitly instruct humanity and procreate among them. The offspring of these unions are the Nephilim, savage giants who pillage the earth and endanger humanity.
Samyaza and his associates further taught their human charges arts and technologies such as weaponry, cosmetics, mirrors, sorcery, and other techniques that would otherwise be discovered gradually over time by humans, not foisted upon them all at once. Eventually God allows a Great Flood to rid the earth of the Nephilim, but first sends Uriel to warn Noah so as not to eradicate the human race. The watchers are bound “in the valleys of the Earth” until Judgment Day (Jude verse 6 says, “And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.”).
1 And all the others together with them took unto themselves wives, and each chose for himself one, and they began to go in unto them and to defile themselves with them, and they taught them charms
2and enchantments, and the cutting of roots, and made them acquainted with plants. And they
3 became pregnant, and they bare great giants, whose height was three thousand ells: Who consumed
4 all the acquisitions of men. And when men could no longer sustain them, the giants turned against
5 them and devoured mankind. And they began to sin against birds, and beasts, and reptiles, and
6 fish, and to devour one another’s flesh, and drink the blood. Then the earth laid accusation against the lawless ones.
The chiefs of tens, listed in the Book of Enoch, are as follows:
7. And these are the names of their leaders: Sêmîazâz, their leader, Arâkîba, Râmêêl, Kôkabîêl, Tâmîêl, Râmîêl, Dânêl, Êzêqêêl, Barâqîjâl, Asâêl, Armârôs, Batârêl, Anânêl, Zaqîêl, Samsâpêêl, Satarêl, Tûrêl, Jômjâêl, Sariêl. 8. These are their chiefs of tens
- R. H. Charles translation, The Book of the Watchers, Chapter VI.
The account of the Book of Enoch has been associated with the passage in Genesis 6:1-4, which speaks of Sons of God instead of Watchers:
When men began to multiply on earth and daughters were born to them, the sons of God saw how beautiful the daughters of man were, and so they took for their wives as many of them as they chose. Then the Lord said: “My spirit shall not remain in man forever, since he is but flesh. His days shall comprise one hundred and twenty years.” At that time the Nephilim appeared on earth (as well as later), after the sons of God had intercourse with the daughters of man, who bore them sons. They were the heroes of old, the men of renown.— Genesis 6:1–4
The Sons of God and the Daughters of Men (Genesis 6:1-8)
The ‘sons of God’ of verses 2 and 4 are fallen angels, which have taken the form of masculine human-like creatures. These angels married women of the human race (either Cainites or Sethites) and the resulting offspring were the Nephilim. The Nephilim were giants with physical superiority and therefore established themselves as men of renown for their physical prowess and military might. This race of half human creatures was wiped out by the flood, along with mankind in general, who were sinners in their own right (verse 6:11,12).
The Apocrypha and Pseudepigrapha of the Old Testament can be found here on the link below. I will soon add a PDF which is easier to read and work with.
The blog below is very interesting.