Sumerfag here
You need to read up on your history. During the Renaissance anything that was non-Christian was labeled "paganism" because of the lack of understanding of ancient cultures. There was no witchcraft involved in Sumer, as a matter of fact Yahweh was the original Sumerian god Enki or his son Marduk… Most of the biblical stories were derived from the tales left behind by the Sumerian culture. in Sumer the "Gods" or Annunaki, who mated with the humans produced demigods, not the nephilm. As a matter of fact the word "nephilm" does not appear in any Sumerian texts.