The children of the Nephilim became known as the Titans. This is an important, but endless subject. Most of the posters here will spew all over it. So get ready.
For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark,
And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be.
This is the place where CHRIST warned about this. One of the Biblical reasons for the flood was the Children of the Sons of God. This really proves what a true and uncanny book the Bible is. Most churches will not touch this subject.