There are a lot of blank spaces in Genesis. .Bits and pieces that are mysterious .The serpent-there is no explanation of why he is and why he does what he does. the idea of Satan is a long time coming and would not be what the writer had in mind. Snakes were symbols of fertility cults and pagan practices. could it be that the writer put out a subtle polemic on paganism?How it is poisonous to our relationship with God? What we know about "Creation stories " is that they are very old and were around orally for many centuries.And usually very expansive. What we see written is probably only a small fraction of the original story. These characters and archetypes would be very familiar to the audience.They could fill in any ‘blank spots’ because, culturally it would have been a story that the tribe or grandpa told them and they were completely at home with. What we see written is only bare bones. If we see any iconic name put out like say “Superman”, we know who he is, where he came from what his job is, etc. without having to be told and more of the story- we mentally fill in the blanks.So with Genesis.