Sons Of GOD

Genesis Chapter Six Talks about the Sons of God took Them Wives from the Daughters of Man. Who Were these Sons of God? they say their were giants in the land, we know David fought goliath, was he from the sons of God and a mortal woman? then why was Jesus not a giant?We Know a Third of The Arch angels led By Lucifer Had a Rebellion and were Cast out of Heaven Were did these Fallen Angels go to? Were are they Now? Can there be Demons and Angels among Us Now?