Nephilim. Gen 6:4

Rephaim, a race of giants Deu 3:11

Anakim Deuteronomy 2:21, Joshua 11:21

Emim Genesis 14:5, Deuteronomy 2:10

“Sons of God” were fallen angels (demons) who mated with human females and/or possessed human males and then mated with human females. These unions resulted in offspring, the Nephilim, that were "heroes of old, men of renown" (Genesis 6:4).

The Nephilim were one of the primary reasons for the great Flood in Noah's time. Immediately after the Nephilim are mentioned, God's Word tells us this: "The LORD saw how great man's wickedness on the earth had become, and that every inclination of the thoughts of his heart was only evil all the time. The LORD was grieved that he had made man on the earth, and his heart was filled with pain. So the LORD said, 'I will wipe mankind, whom I have created, from the face of the earth — men and animals, and creatures that move along the ground, and birds of the air — for I am grieved that I have made them'" (Genesis 6:5-7). So, God proceeded to flood the entire earth, killing everyone and everything (including the Nephilim) other than Noah and his family and the animals on the ark (Genesis 6:11-22).

Where there Nephilim after the Flood? Genesis 6:4 tells us, "The Nephilim were on the earth in those days — and also afterward." It seems that the demons repeated their sin sometime after the Flood. However, it likely took place to a much lesser extent than it did prior to the Flood. When the Israelites spied out the land of Canaan, they reported back to Moses, "We saw the Nephilim there (the descendants of Anak come from the Nephilim). We seemed like grasshoppers in our own eyes, and we looked the same to them" (Numbers 13:33). This passage does not specifically say that the Nephilim were genuinely there, only that the spies thought they saw the Nephilim. It is more likely that the spies witnessed very large people in Canaan and mistakenly believed them to be the Nephilim. Or, it is possible that after the Flood the demons again mated with human females, producing more Nephilim. Whatever the case, these "giants" were destroyed by the Israelites during their invasion of Canaan (Joshua 11:21-22) and later in their history (Deuteronomy 3:11; 1 Samuel chapter 17).