At the end of the time of the Second Temple, the association of Azazel as a fallen angel remained partly in Christianity and Islam.
According to non-biblical sources, among others the Apocalypse of Abraham, Azazel is the godless lord of hell, seducer of mankind.
Azazel in the Bible
Azazel (Hebrew ‛ăzā'zē), which means "departure" or "rapture," is used in Scripture in reference to the annual ceremonial scapegoat rite that was offered as a sacrifice to maintain the holiness of the sanctuary, purify Israel, and atone for their sins.
On the way to the promised land, YAHWEH gave the law to Moses and asked Aaron to sacrifice two goats. The first goat was offered as a sacrifice for the atonement of sins, while the second goat carried the sins of the people, which had been transferred through prayer.
Contrary to popular belief, in the Bible the goat of Azazel does not represent Christ, for a number of reasons:
1) The scapegoat is used in opposition to YAHWEH, and is also the opposite of YAHWEH:
Leviticus 16:8 "After Aaron casts lots for the two goats, one for the LORD and the other for the scapegoat"
2) The blood of the goat offered to the Lord was poured out to purify the sanctuary entirely before the scapegoat was introduced into the ritual.
3) The goat offered to the Lord was presented as a burnt offering atonement. As the goat was kept alive, the high priest placed his hands on the head of the goat, symbolically imputed to it the sins of the children of Israel and then released the goat into the wilderness by a strong man.
Leviticus 16:10 "But the goat chosen by lot as the scapegoat shall be presented alive before the LORD to make atonement by sending it into the wilderness as the scapegoat."
Leviticus 16:21-22 "Then he is to lay both hands on the head of the live goat and confess over it all the iniquities and rebellious acts of the Israelites in regard to all their sins. He is to put them on the goat’s head and send it away into the wilderness by the hand of a man appointed for the task. The goat will carry on itself all their iniquities into a solitary place, and the man will release it into the wilderness."
Azazel according to the Book of Enoch
According to the Book of Enoch, which was removed from the Catholic canon in the 4th century but preserved by rabbinic Judaism and the Ethiopian and Eritrean Orthodox churches, Azazel is the instigating angel and leader of the angels who led the pre-flood world to perdition.
After the fall of Lucifer/Satan (the spirit of evil), Adam and Eve are placed in the Garden of Eden to dwell in it. Filled with covetousness, Satan influences the serpent who deceives Eve, who in turn deceives Adam. All of them are cursed, cast out of the Garden and cast down to inhabit the earth. Adam and Eve begin to procreate and the human race starts to multiply. YAHWEH assigns a number of angels to watch over mankind because they are not safe from Lucifer/Satan (the spirit of evil), however, this group of angels (called the watchers) fell in love with some human women. Azazel incited his companions to engage in illicit sexual relations with some women and they gave birth to giants.
Genesis 6:2 "The sons of God saw that the daughters of men were beautiful, and they took as wives whomever they chose."
Genesis 6:4 "The Nephilim were on the earth in those days—and afterward as well—when the sons of God had relations with the daughters of men. And they bore them children who became the mighty men of old, men of renown."
In the Testament of Reuben son of Jacob, it is written that these angels would take on human forms with considerable sexual organs and would appear to these women while they were having intimate relations with their husbands. These appearances aroused in these women the sexual desire for the angels.
Apart from fornication and adultery, the angels taught their human concubines all kinds of arts: the making of the sword, the shield and the breastplate, the making of jewels, make-up, the importance and the use of precious stones, witchcraft and the concoction of potions and herbal remedies, astrology... (the book of Enoch chapter 8).
YAHWEH imputed all sins to Azazel, and kept him in chains until the end of time
The Book of Enoch chap10:4-6 "And further the Lord said to Raphael: "Bind Azazel by his hands and his feet and throw him into the darkness. And split open the desert, which is in Dudael, and throw him there. And throw on him jagged and sharp stones and cover him with darkness. And let him stay there forever. And cover his face so that he may not see the light. And so that, on the Great Day of Judgment, he may be hurled into the fire."
Jude 1:6 "And the angels who did not stay within their own domain but abandoned their proper dwelling—these He has kept in eternal chains under darkness, bound for judgment on that great day."
2 Peter 2:4 "For if God did not spare the angels when they sinned, but cast them deep into hell, placing them in chains of darkness to be held for judgment"
In order to purify the earth from the teachings of Azazel, YAHWEH commanded to open the floodgates of the heavens and that a worldwide flood sweep away the entire world except for Noah, his wife, his 3 sons and their wives, as well as some couples of animals. This was done to ensure the continuation of life on earth.
May the Holy Spirit guide you in the understanding of this message. 🙏