The Grigori are an advanced species of humanoids from a world beyond the star system of Earth. They are referenced in the Bible as the “Fallen Angels”. Per Christian mythology the Grigori males found human females to be very attractive and either raped or married as many human females as they could. The union produced a hybrid species who were called the “Nephilim”.
Christian myth mentions the Nephilim, who were giants compared to men throughout the Bible. The flood account was exposed as an attempt to destroy the corrupted hybrid line. The Isrealite David slew the giant Goliath who was himself Nephilim.