The Emim, Anakim, Rephaim.
It seems possible that these people(s) are related in some way to the Nephilim. Why are there different names, if they are the same people?
Firstly, it is possible that they were known by different names in different parts of the country.
Secondly, it is possible that the different names relate to the extent to which they have descended from the Nephilim. By this, I mean that if the Nephilim mated and bred with humans, and their offspring mated and bred with other humans, eventually the Nephilim genes may have become "diluted" as the successive generations continued to mate and breed solely with humans.
I was interested by the comment about the fallen angels censoring the Bible to remove any trace of themselves. If this is so, they did not do a very good job of it, as the references still remain! Also, who were/are they who are continuing to censor the Bible?
Regarding the comment about the fact that the Nephilim should have been destroyed in the Flood, the Bible states that all men/mankind were destroyed in the Flood except for Noah and his family. I take this to mean humankind, therefore some, but not all, of the Nephilim could have survived the Flood without it contradicting the Bible's version.