The story of the Watchers, as chronicled in the Book of Enoch and mentioned briefly in the Bible, is a myth about fallen angels. It's less-known and less often referenced than the story of the War in Heaven and the fall of Lucifer, but it's a curious story. A group of around 200 angels, called the Watchers (or Grigori, “those who are awake”) come to Earth to teach humanity the arts and sciences, but they sin and are permanently banished from heaven. Chapter 69 of Enoch explains that teaching humanity heavenly mysteries is itself a transgression, like Prometheus bringing fire to humans. Similar to Prometheus, Azazel is harshly punished for teaching humanity warfare and beautification, which are described as the source of sin (and Azazel is often an evil demon in the media). There is also a long rant in chapter 69 about the angel who taught writing to humanity, and how the knowledge of writing causes humanity to sin. The disturbing implication of this is that knowledge is sinful.
However, the Watchers are more famously punished for another transgression—having sex with human women. This is the part of their story mentioned in the Bible. Their half-human, half-angel children are described as bloodthirsty giants, called “Nephilim” in the Bible. In Enoch the Nephilim are pure evil and the cause of the Flood, but in the Bible they are mentioned to be “the heroes of old, men of renown.” A vast majority of Classical heroes were demigods. This series tells the story of how a love between Samyaza, leader of the Watchers, and Naamah, granddaughter of Caine, led to the war between the gods, the angels, and men and caused the great flood of Noah.