Watcher are said to be some of the fallen angels who rebelled against God. Some are considered good, others evil, and they have been referred to in different parts of the Bible and other religious texts.
Most of the information about the Watchers is found in the Book of Enoch, a non-canonical, apocryphal works. Enoch was the great-grandfather of Noah who gathered secret knowledge, which included details about the Watchers and some of their names, but not all 200. They were fifth in heaven when they rebelled and the fall took place, however not all watchers fell and they are referred to in the Third Book of Enoch.
The Watchers were angels instructed to watch over human and soon lusted after human women. Prodded by Semyaza and Azazel, who was later considered to be a demon or as Lucifer (the Lightbringer) or Lumiel (light of God). They came to Earth on Mount Hermon and mated with human women producing hybrid, savage giants known as the Nephilim.
The Angels then taught women charms, enchantments, the cutting of roots, and the knowledge of plants. They taught men how to make various weapons and armor, and also arts and sciences. These acts led to an increase in lawlessness and warfare. The men of earth then cried out to heaven, and the 4 archangels (Michael, Uriel, Raphael, and Gabriel) cried out to God. In response, God sent Uriel to warn Noah that there would soon be a flood that would destroy the wickedness on earth.
Human would have eventually discovered these technologies but at a much slower pace.
The race of giants produced from this union gave way to a brood of evil spirits. The evil spirits most likely are the departed spirits of the giants, themselves. These spirits are not material or corporeal beings, but they torment mankind because they have proceeded from them.
Names of the Fallen Angels (aka the Five Satans); Yeqon, Asb’el, Gader’el, Pinem’e and Kasadya.
Names of other fallen angels – Semyaz, Aristaqis, Armen, Kokba’el, Tur’el, Rumyal, Danyul, Neqa’el, Baraqel, Azaz’el, Armaros, Betryal, Basas’el, Hanan’el, Tur’el, Sipwese’el, Yeter’el, Tuma’el, Tur’el, Rum’el, and Azaz’el – 1 Enoch 69:2
Stranger Than Fiction Stories by M.P. Pellicer