What is The Nephilim, they were the offspring of the “sons of God” and the “daughters of men” before the Deluge?
According to Biblical information Nephilim (or Fallen Angels) were products of interaction between Angels and Humans. They were giants and great warriors.
Genesis 6:4 The Nephilim were in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
The book of Enoch section 2 chapter 6 gives us an explanation of who and what were The Nephilim, And it came to pass after the children of men had increased in those days, beautiful and comely daughters were born to them. And the angels, the sons of the heavens, saw and lusted after them, and said one to another: Behold, we will choose for ourselves wives from among the children of men, and will beget for ourselves children. And Semjâzâ, who was their leader, said to them: I fear that perhaps ye will not be willing to do this deed, and I alone shall suffer for this great sin. Then all answered him and said: We all will swear an oath, and bind ourselves mutually by a curse, that we will not give up this plan, but will make this plan a deed. Then they all swore together and bound themselves mutually by a curse, and together they were two hundred.
Numbers 13:33 And there we saw the giants, the sons of Anak, which come of the giants: and we were in our sight as grasshoppers, and so we were in their view.
Genesis 6:3 And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be a hundred and twenty years.
Here in the book of Genesis 3:15 God told us what he would do to the Fallen Angels that mate with human females. He said, and I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.