Quote Originally Posted by Millstone85 View Post
The creator of the couatls was, of course, Quetzalcoatl. He was also the lone good-aligned god of the yuan-ti.
So it turns out that 5e's mysterious couatl god had a name in previous editions. It is Jazirian. And to my surprise, some legends portray him as the creator of the Great Wheel, no less, together with his evil twin Ahriman (who may or may not be Asmodeus' true identity). Those two are said to be recovering from the fight they had after the Wheel was completed, now biting their own tails instead of each other's, one on Mount Celestia and the other deep in the ninth hell.

Also, couatl yuan-ti are totally a thing. They are called shulassakar on Eberron.

That's all really cool!

Now, I guess that a common headcanon must be that there was a third great serpent working with them. Trinity, rule of three, and all that. My own take is that the third serpent is... Sigil, also biting her own tail, with the Lady of Pain as a servant or avatar.