In the Hebrew Bible, the name Azazel represents a desolate place where a scapegoat bearing the sins of the Jews was sent during Yom Kippur. During the late Second Temple period, Azazel came to be viewed as a fallen angel responsible for introducing humans to forbidden knowledge, as described in the Book of Enoch. His role as a fallen angel partly remains in Christian and Islamic traditions.
"And Aaron shall cast lots over the two goats, one lot for the LORD and the other lot for Azazel." Lincoln Cathedral
Mount Azazel (Jabel Munttar) in the Judean Desert
Cliffs of Mount Azazel (Jabel Munttar)
Illustration of Azazel in Dictionnaire infernal by Collin de Plancy (1863)
Fallen angels are angels who were expelled from Heaven. The literal term "fallen angel" does not appear in any Abrahamic religious texts, but is used to describe angels cast out of heaven or angels who sinned. Such angels often tempt humans to sin.
The Fallen Angels (1893), by Salvatore Albano. Brooklyn Museum, New York City
Fountain of the Fallen Angel (1877), by Ricardo Bellver. Retiro Park, Madrid, Spain
Chester Beatty XII, Greek manuscript of the Book of Enoch, 4th century
The Fall of the Rebel Angels (Apocryphal) (c. 1250), by William de Brailes. God sits on a throne within a mandorla. The rebelling angels are depicted as falling out of heaven and into a hell, in the shape of a mouth. As they fall, the angels become demons.