I have a brain worm -- I am trying to think of a book series, what I can remember is:
In the late 80's early 90s I read a fantasy series as a young adult that involved a battle between a winged serpent / quetzalcoatl god and his nemesis.
To my recollection the main protagonists were on some kind of quest for the winged serpent god while being chased or followed by the nemesis god's agents.
I recall that in the final book they basically call out both gods as their war is destroying everything else.
I think this was part of a series made up of 2-4 books.