Faraer said:
'Satan' is also a title, in fact an ordinary Hebrew noun meaning 'adversary', and the idea of a single Satan and its conflation with Lucifer is an error made in the early Christian era. The 'God vs the Devil' thing is far more a Persian idea than a Jewish one.
Another scholarly error that became theology, or folklore, and has hard remarkable sticking power is the translators of the King James Bible's mistaken conjecture that the Hebrew name for God, the Tetragrammaton YHVH, is pronounced 'Jehovah'.
'I'. 'J', and 'Y' are all the same letter in Latin - it was only later that a seperate pronunciation of the three took place. For that matter W used to literally be a double U. (And pronounced oo.)
I actually knew that Satan was a title, but misplaced the neurons responsible for remembering it, those neurons have since been fired. The Adversary was a job handed out by God, not a rebellion against him. The angel stuck with the job, an I recall correctly, also changed on occassion. I once saw a description of angels as Gods hitmen... in some ways a fair description.
Yes, the good/evil aspect was largely Zoroasteranism (sp?), Ahura Mazda and Ahriman. Though 'demons' as evil spirits do also occur in the Bible, Asmodeus in the book of Tobit being the one that comes to mind. It was only after Christianity attempted to place these spririts into an heirarchy that the whole thing became the mythology we are familiar with. Babylon, and Persia both left their marks, Llith being one of the most notabe (They are seven, they are seven, they are seven times seven... was a description of the Babylonian 'demons'. (Daemon is actually Greek.))
Oddly, some of the early Christian appearances of Satan took the view that not only might he be forgiven, but that it was inevitable that eventually he would ask forgiveness, and that it would be granted. I have encountered at least one Catholic priest who still holds to this view.
It helps when you realize that much of the 'ending of the world' described in the New Testament actually refers to Rome, not the world in general. But writing about the end of the world was safe, while writing about the end of Rome could get you crucified.
And an amusing detail - Pontius Pilate, the judge who sentenced the Christ to crucifiction was himself eventually brought to trial and allowed to commit suicide - for the crime of leniency. Considering that in all likelyhood the trial was not about claiming to be the Son of God, but rather claiming to be the King of the Jews (there already was one - Herod) the fact that Pilate alowed him a chance to recant that stance was an exception to the Roman norm. They were the people who brought us the word 'decimate', meaning to kill one in ten.
The Auld Grump, one of the descriptions of Pazuzu the demon/god of plague described him as having a 'great sense of humor'...