His mother was Cihuacoatl. By Xochiquetzal, he was the father of Quetzalcoatl. By Coatlicue, he was the father of Huitzilopochtli.
There was also a legendary Chichimeca leader during the Toltec period named Mixcoatl who, with Chimalman, gave birth to Topiltzin Ce Acatl Quetzalcoatl. The story of his life mirrors closely the story of his devine counterpart (they both slay the goddess Itzpapalotl and give birth to a Quetzalcoatl, for instance) and one may well have been the inspiration for the other.
His name means "Cloud Serpant", referring to the Milky Way with which he is identified.