Jesus said "as it was in the days of Noah" The Genesis account explicitly says; "the earth was filled with Violence and was corrupt in the sight of God, for all Flesh had corrupted their way”....... Gen6:11,12
The word says that "All Flesh had corrupted their way".. It does not say that all flesh became corrupt by DNA manipulation of fallen angels... It was their way (their conduct) that had become corrupt..I am of the opinion that ‘corruption of the flesh’ equates to the wickedness of men.."God saw that the wickedness of Men was great upon the earth" This is what God said previously. Gen6:5 This wickedness was contained in the thoughts and imagination of men were continually Evil and men had become violent.
TheApostle Peter applies this concept of wickedness in the days of Noah and refers to it as “the world of the ungodly” 2Pet2:5 … This is in reference to the various races of men who had perverted the 'way' of righteousness.. That is indicative by the fact that only Noah and his household were found to be righteous.. This is the contrast to be apprehended (The righteousness of Noah & wickedness of Men)
Jesus referred to the days of Noah as a time when people were “eating, drinking and marrying and not a world ruled by the Nephilims.
The scriptures I have provided are in prompt context and without speculation and indicative of the various races of men who had perverted the way of righteousness and that this was the purpose of God for sending the Flood.
I maintain that the Neplilim were a race of men, their lineage can be traced in the book of Joshua14:15, 15:13, Judg1:10
Arba was the father of Anak who was part of the Nephilim.