This story is about souls being produced by- and souls being rescued from the realm of nature with its inherent animal urges. Az, -living nature- saw herself being diminished with every soul leaving her realm and she wasn't to happy about it.

Az, the evil mother of all demons, grew angry and raged for her own purposes. From the dirt of male and female demons she made this body and entered it. Then from the five elements of Light, Lord Ahura Mazda’s armor, she formed the good soul  and chained it into the body. She made the first man like someone blind and deaf, unconscious and deluded that from the beginning he might not know his true origin and family. She created the body as a prison and chained the grieved soul into it. “My jailers are robbers, male and female demons, witches!” Firmly she chained the soul into the fraudulent body and made it hateful and evil, angry and vengeful. But lord Ohrmuzd (Ahura Mazda) had mercy on the souls, and came down to Earth in human form. He maimed the evil Az. Then he revealed to man and woman all that was and will be. He quickly showed that this body of flesh was not made by lord Ohrmuzd, nor was the soul chained by him. Mani; Adam, child of demons and his salvation. Manichaean creation myths, The other Bible.  

Enlil; the animal soul; animal life and Ninlil; vegetable life and fertility (sexual drive) of course were two aspects of a unity, two sides of a coin and therefore hard to distinguish from each other. Male and female.

At the time, Azael (Shemiaza) and Azazel descended to Earth, people must have thought that god himself, his wife and consorts had descended to Earth. At that time the highest known god was Enlil; Ahriman whose wife was named Az. In Babel however, the city of Babylon (Gate of the gods) had just become the most important political center of the region. The most important god there was Marduk, who, as a result, had begotten the Enlilship, the kingship of Earth and his magical name was Asaluhi. He actually was the same as Ninazu (Ninurta) who according to their mythology previously had destroyed Anzu for stealing the tablets of destiny from Enlil. As a reward, Ninazu became the "shepherd" of mankind. Marduk (Asaluhi) / Ninazu; Lord Azu or Azael became the new Enlil, the new god on earth. Their consorts, the Anunaki are still known as the Aesir of Norwegian mythology. Because things didn't work out as planned, Azael, Azazel and their Nephilim; NinAzu, his wife Ninsutu (Osiris and isis) and their Anunaki became known in Jewish Christian accounts as Satan and his angels who had fallen to Earth. It looks like Satanail, the Prince of the Nephilim, or Enlil, the first of the Anunaki had incarnated here on Earth as the new gods who seemingly had taken over his power under the names of Marduk (Zisi), Zeus, Osiris and Isis.

And behind the tree was standing (something) like a dragon in form, but having hands and feet like a man’s, on his back six wings on the right and six on the left. And he was holding the grapes of the tree and feeding them to the two I saw entwined with each other. And I said, “Who are these two entwined with each other, or who is this between them, and what is the fruit which they are eating, Mighty One, Eternal?” And he said. “This is the world of men, this is Adam and this  is their thought on earth, this is Eve, and he who is between them is the impiety of their behavior unto perdition, Azazel himself.” Apocalypse of Abraham. 23;1

Though Enlil/Satan, the entity of animal life; animal soul, originally was a good angel (he was the first Son of Anu and Ki; the Spirit and the earth), he more and more became an obstacle for evolving souls to ascend, leave this earthly plane and escape his influence. He saw himself diminished and got jealous, so to speak. It appears as if -Ahriman, Satan, Enlil, etc. etc.-, married to - Az, Lillith, Ninlil, Danu etc. etc.; Nature - wanted to secure their Kingship over the physical world, the Earth by having mentally high developed beings; -NinAzu, Zeus, ShemiAza and Azazel; Osiris and Isis, etc. etc.- descended to Earth in the form of their physical sons and daughters; races of other worlds, that were chased out of their original habitat in the heavens. They ruled mankind until things really went wrong and God, at the request of Satan/Enlil himself, put an end to it, by allowing him to flood the Earth, but destroying their offspring in the process.

On the other hand, it could also be that in long forgotten times travelers from Space descended here on Earth after having been forced to escape a major disaster for instance a meteor storm hitting their habitat somewhere in the direction of Orion or, as close as the Moon. They probably were "normal people" just like the rest of us, though much more evolved, but just making the best of it. Soon enough they organized themselves and started meddling with our evolution for their own purposes and taught us their "wisdom and knowledge from the heavens", creating physical- as well as mental giants, half-breeds, heroes and demigods to do their bidding. It didn't take to long before their plans ended up in gigantic power struggles, full scale wars and utter destruction and misery here on this Planet. These Aliens, though first being held to be gods, soon fell from their thrones and were named by the people after the demons they knew from their own mythologies and religions.