Wow! This bears a striking similarity to some apocrypha (idk the plural). Where Nephilim (like Moses or Noah - don’t remember who, but it was the one who was very very old and had many kids with a young woman - was supposed to be one) are mentioned, giants, half-gods. And in order to be wiped off the face of earth, “the one and only” flooded the planet, but Noah built the ark and survived.