In string theory, it is the vibration of cosmic strings which cause what we see as forces and particles of matter. When cosmic strings interact, they can cause a membrane to be formed, which then twists into a coiled or tubelike form. I understand the serpent symbol as it relates to the structure of matter to represent this coiled membrane.
However, in all of my study of the original Dogon and Egyptian symbols, I have found no lurking darkness of any kind - only what seems to have been a sincere, bonafide effort to help us understand. But that effort seems to have gone against a specific prohibition, and triggered later steps by some other group to reverse/discredit/vilify that effort. It is these secondary efforts that I associate with darkness.