Ok, this means a lot for religious people. The Nephilim were a group of angels that were thrown from heaven and had sex with men. The resulting children were magically gifted with powers from heaven and were an abomination to God. The world became overrun with them, and that is why God decided to flood the earth during the days of Noah. That's what has been taught. If you can tell, the Angel has elements of human sexuality, but isn't human itself. Man is fallen and entangled with the snake - satan. The theory is that a Nephilim is the one being that can stand against God - a bastard child of heaven and earth.