A few small points.
The reference to "Samyaza" in the "Book of Enoch" is more accurately to "Shemihazah," the fallen watcher in 1 Enoch who led the watchers down from heaven to mate with mortal women. His name has something to do with seeing and "My name." "Samyaza" is a later form of the name, I think(?) the form in the Ethiopic translation of 1 Enoch.
There is no reference to Mastema in the Book of Watchers (which is the first section of 1 Enoch). He does appear in Jubilees and in the Dead Sea Scrolls. The words Satan and Mastema come from two different, but very similar, Hebrew roots (√śṭn and √śṭm, respectively). The roots have different, but very similar meanings ("to be an adversary to" and "to be hostile to," respectively).
For many past PaleoJudaica posts on the Devil/Satan (a.k.a. Azazel, Belial, and Beelzeboul) start here and follow the links.
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