Book of Enoch
Main article: 1 Enoch
The term "Watchers," is common in the Book of Enoch found among the Dead Sea Scrolls, and the Book of the Watchers is the name for one section of the book (1 Enoch 6-36). It occurs in the Aramaic fragments in the phrase irin we-qadishin, "Watchers and Holy Ones", known from Aramaic Daniel. The Aramaic irin "watchers" is rendered as "angel" (Greek angelos, Coptic malah) in the Greek and Ethiopian translations, although the usual Aramaic term for angel malakha does not occur in Aramaic Enoch. The dating of this section of 1 Enoch is around 2nd-1st Century BCE. This book is based on one interpretation of the Sons of God passage in Genesis 6, according to which angels married with human females, giving rise to a race of hybrids known as the Nephilim. The term irin is primarily applied to disobedient Watchers who numbered a total of 200, and of whom their leaders are named, but equally Aramaic iri ("watcher" singular) is also applied to the obedient archangels who chain them, such as Raphael (1 Enoch 22:6).
Genesis 6, the Sons of God
Main article: Sons of God
The watchers story in Enoch derives from the sixth chapter Genesis, where the "Origin of the Nephilim" is described and the "Sons of God" who beget them are mentioned:
When men began to multiply on earth and daughters were born to them, the sons of God saw how beautiful the daughters of man were, and so they took for their wives as many of them as they chose. Then the Lord said: "My spirit shall not remain in man forever, since he is but flesh. His days shall comprise one hundred and twenty years." At that time the Nephilim appeared on earth (as well as later), after the sons of God had intercourse with the daughters of man, who bore them sons. They were the heroes of old, the men of renown. (Genesis 6:1-4)
Here, the "sons of God" are given no specific name or function; they could represent fallen angels, heavenly beings that mate with human women. The Book of Enoch regards these as the same angels who are referred to as the Benei Ha-Elohim (Eng. Sons of God) in the Book of Genesis. According to this belief, their sins filled the Earth with violence and the world was destroyed as a result of their intervention.
Names of 1 Enoch Watchers
In the Book of Enoch, the watchers are angels dispatched to Earth to watch over the humans. They soon begin to lust for human women, and at the prodding of their leader Samyaza, they defect en masse to illicitly instruct and procreate among humanity. The offspring of these unions are the Nephilim, savage giants who pillage the earth and endanger humanity. Samyaza and associates further taught their human charges arts and technologies such as weaponry, cosmetics, mirrors, sorcery, and other techniques that would otherwise be discovered gradually over time by humans, not foisted upon them all at once. Eventually God allows a Great Flood to rid the earth of the Nephilim, but first sends Uriel to warn Noah so as not to eradicate the human race. While Genesis says that the Nephilim remained "on the earth" even after the Great Flood, Jude says that the Watchers themselves are bound "in the valleys of the Earth" until Judgment Day. (See Genesis 6:4 and Jude 1:6, respectively)
There are 20 leaders in the Book of Enoch also called 1 Enoch the section that mentions them
“ 7. And these are the names of their leaders: Sêmîazâz, their leader, Arâkîba, Râmêêl, Kôkabîêl, Tâmîêl, Râmîêl, Dânêl, Êzêqêêl, Barâqîjâl, Asâêl, Armârôs, Batârêl, Anânêl, Zaqîêl, Samsâpêêl, Satarêl, Tûrêl, Jômjâêl, Sariêl. 8. These are their chiefs of tens." - R. H. Charles translation, The Book of the Watchers, Chapter VI. ”
These are the leaders of 200 angels in 1 Enoch that are turned into fallen Angels because they took wives, mated with human women, and taught forbidden knowledge.
Araqiel (also Arakiel, Araqael, Araciel, Arqael, Sarquael, Arkiel, Arkas)  taught humans the signs of the earth. However, in the Sibylline Oracles, Araqiel is referred to not as a fallen angel, or Watcher, but as one of the 5 angels who lead the souls of men to judgement, the other 4 being Ramiel, Uriel, Samiel, and Azazel.
Armaros (also Amaros) in Enoch I taught men the resolving of enchantments.
Azazel taught men to make knives, swords, shields, and how to devise ornaments and cosmetics.
Gadriel taught the art of cosmetics.
Baraqel (Baraqiel) taught men astrology
Bezaliel mentioned in Enoch I, left out of most translations because of damaged manuscripts and problematic transmission of the text.
Chazaqiel (sometimes Ezeqeel) taught men the signs of the clouds (meteorology).
Kokabiel (also Kakabel, Kochbiel, Kokbiel, Kabaiel, and Kochab), is a high-ranking, holy angel but, in general apocryphal lore and also in Enoch I, he is a fallen Watcher, resident of nether realms, and commands 365,000 surrogate spirits to do his bidding. Among other duties, he instructs his fellows in astrology.
Penemue "taught mankind the art of writing with ink and paper," and taught "the children of men the bitter and the sweet and the secrets of wisdom."
Sariel (also Suriel) taught mankind about the courses of the moon (at one time regarded as forbidden knowledge).
Samyaza (also Shemyazaz, Shamazya, Semiaza, Shemhazi, Semyaza and Amezyarak) is one of the leaders of the fall from heaven.
Shamsiel, once a guardian of Eden, served as one of the 2 chief aides to the archangel Uriel (the other aide being Hasdiel) when Uriel bore his standard into battle, and is the head of 365 legions of angels and also crowns prayers, accompanying them to the 5th heaven. He is referred to as one of the Watchers. He is a fallen angel who teaches the signs of the sun.
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