Does it seem farfetched to assume the ancient myth of the Greeks could be derived by stories of these beings?
Bigtime As I remember from Genesis, the Nephilm were demi-gods (half-god, half-human). They were also sea people- more mobile than any in that static age. They were probably were the Sea Peoples of the late Bronze Age (c. 1200 BCE). The Philistines were one and left Crete for Palestine as the Hebrews arrived. Since the Titans were Greek, I would say "Yes"...
I don't see any reason to assume that the Titan myths were derived from the Nephilim myths. It might have been the other way around. But more likely, both the Hebrews and the Greeks derived these similar mythological ideas from earlier legends that were probably already thousands of years old by their time. My impression is that both the Hebrew and Greek versions are rather late. The idea that there's more than one pantheon and that the different orders of gods struggled against one another is very widespread and appears to be very old. There's also the Devas and Asuras in India, as well as the Aesir and Vanir in Germanic mythology, and probably many more examples. Perhaps it originated in a stone-age reaction to religious diversity. Tribes had their own gods, but encountered different tribes who worshipped different gods. So the idea might have risen that there are different castes or orders of gods. Each ethnic group probably assumed that they worshipped the highest and best sort of gods, but still recognized that there were lesser gods around, perhaps bumped out of the highest heavens and not happy about it.
