Nyx

So how did Nyx evolve from a primordial goddess, preceding the Titans and Olympians, to the modern goddess of witches and vampyres?
It is said that Nyx is older and more powerful than Zeus and that he feared going into her cave and angering her. Nyx was night itself.
In research, I have seen the spelling of the deity name as both “nyx” and “nix.”

In my book, The Goddess Aped, I postulate that the goddess known as Aphrodite is the actual primordial goddess. What documentation do I have to back up this theory? The ancient birth myth of the god Eros. His origin myth evolved from being born of Nyx to being born of Aphrodite.