There are a lot of passages that talk about Satan, but they tend to be contradictory.
1) the adversary playing the role of prosecuting attorney in a heavenly court with God and the angels (Job 1:6 & Zechariah 3:1-2 & 1 Peter 5:
2) as the devil (from the Greek "diabolos" which means "slanderer"), the tempter of Jesus (Matthew 4:1-3, Luke 4:2)
3) the prince of the demons, Beelzebub (Matthew 12:24, Mark 3:22, Luke 11:15)
4) unclean spirit (Matthew 12:43)
5) the evil one (Matthew 13:19 & 1 John 2:13)
6) the author of all evil (Luke 10:19)
7) a murderer and the father of lies (John 8:44)
the prince of this world (John 12:31 & 14:30 & 16:11)
9) a demon able to enter into a human body (John 13:27)
10) god of this world (2 Corinthians 4:4)
11) Belial (2 Corinthians 6:15)
12) prince of the powers of the air, the spirit that now works in the sons of disobedience (Ephesians 2:2)
13) power of darkness (Colossians 1:13)
14) an adversary, like a roaring lion who walks about seeking whom he may devour (1 Peter 5:
15) the angel of the abyss, named Abaddon in Hebrew, Apollyon in Greek (Revelation 9:11)
16) a great red dragon (Revelation 12:3 & 12:9 & 20:2)
17) the accuser of our brethren who accuses Christians before God day and night (Revelation 12:10)
18) the dragon, the old serpent (Revelation 20:2)
The bible also lists conflicting attributes for Satan
1) He is a created being, a former Archangel, and thus is inferior to God.
2) He can be only in one place at one time.
3) He has limits to his knowledge and power
4) Satan cannot perform any acts unless God approves (Job1:6 to 2:10).
5) He is a trickster and an unreliable source of information. John 8:44 speaks of him as a liar, the father of all lies.
6) He is the ruler of the earth (John 12:31, Ephesians 6:12 and 2 Corinthians 4:4)
7) He leads a personal army of demons (Matthew 12:24)
He can adopt a spirit form, reside inside a person and influence their thoughts and behavior:
9) Ephesians 2:2 describes him as a spirit who works within "the children of disobedience."
10) John 13:2 describes how Satan "put into" Judas Iscariot's mind the decision to betray Jesus.
11) Acts 5:3 describes how Satan filled Ananias' heart with the decision to lie to the Holy Ghost about the proceeds of a real estate sale
12) His existence places humans in extreme peril.. 1 Peter 5:8 describes him as a dangerous entity, a roaring lion, who roams all over the earth "seeking whom he may devour."
This (the above writing ^) is a copied list from "Sacred Origins of Profound Things" by Charles Panati not one that I put together myself.
This first part of this history of Satan has been previously posted by me (several times lately, though I always stopped after the beginning): I'll add in the rest at the bottom.
The word satan in Hebrew means "to oppose". In certain Greek translations of the old hebrew writings they translated it to mean 'diabolic' but I'm not sure why, exactly. But the word satan was also used as a noun to refer to someone who was an accuser or an adversary. This isn't meant to necessarily reflect an evil person, just someone who is on the other side. For example in a debate you would refer to the other side as your 'satan'. This actually occurs several times in the OT. In Samuel 29:4 the phillistines are distrustful of David, fearing that he would be a satan to them. And in Samuel 19:22 Shime-i apologizes to King David, who rejects the apology, saying that they should not be a satan to each other.
In the Old Testament there is no mention of Satan ever being evil or doing evil deeds himself. Satan is one of gods chief angels (kind of like his enforcer). At worst he's shown to be a henchman who does all of gods dirtywork. You see this is because the Jews had a very different idea of god at that point. The god of the old Jews was viewed as being a sort of personification of the universe. He represented everything and had aspects of everything, thus god was capable of being loving and kind, but he was also a vengeful prick at the same time. This is why you get lines in the old testament where god claims to be both light and dark, where he claims to have created evil and be vengeful, and so on. Because he is all of these things, that was the point.
Historians think that the idea of hell comes from an Indo-European invasion that occurred around 2000BC which displaced the Kurgan peoples. The Kurgans were Hindus (sort of) but when they settled in europe their religious beliefs began to change. The ones who settled in western Europe eventually became the Celts and it's believed that Druidism and Wicca come from them and their beliefs. The ones who settled in the middle east changed as well and eventually developed the concept of salvation and damnation after death. They believed there was a place called the "Bridge of the Petitioner" which you would pass over and be judged by the god, Rashu. Those who failed would be tossed off the bridge into damnation. It should be mentioned that hell, damnation, and eternal life are not concepts that exist in the OT.
As for Satan, around 650-500 BC the Jewish peoples became friends with the Persians. The Persians at that time followed Zoroastrianism, which is the oldest known religion and probably the most influential to other cultures. The religion only enters historical record for the first time around this point, but it existed as far back as around 2000 BC to the knowledge of historians. Anyway back on track, the Zoroastrian religion is based on a dualistic approach to the universe, there is a main god who is a being of pure good and kindness named Ahura Mazda, he basically had all of the qualities that christians claim god has, except with a better back story and cooler name. His opposite was his twin brother Angra Manyu (Or sometimes called Ahriman). He of course was the creator of all that was evil and a general uncool dude. The Zoroastrians believed that the two gods would fight until the god of evil was eventually defeated at which point there would be a Final Judgement. And yes, the NT writers basically just copy-pasted the Zoroastrian version of the end times into their holy text.
Because the Jews and Persians were friends the Zoroastrian religion began to influence their own. This is where you get the NT portayal of god as being an entity of pure good and loving and blah, blah, blah. But that then meant that he needed an evil opposite. So it became Satan since he was probably the best target since his name means 'adversary'. What they never considered was a motivation for Satan being evil. Seriously, they never give him one, he just becomes stupidly evil for no reason they ever bother to explain and all of that 'Gods Chief Angel" stuff just gets swept under the rug. The Bible mentions Satan being cast down from heaven, but like I said it's only mentioned to happen at the end times. The idea of Satan rebelling against god because he was jealous of humans when god created them in the beginning comes from Paradise Lost, but has no biblical backing at all.
The stuff following is stuff I haven't written on here before.
Typically as religions develop the gods of previous religions are relegated to the status of demons in the new one. Many of the descriptions of Satan's appearance come from the Greek god Pan (goat-hooves, horns, personification of lust, etc.) Many former gods became different names applied to Satan. Beelzebub is generally believed to have come from the ancient god Baal and a combination of the Isrealite word 'zebul' which means "dung". Essentially the name Baal-zebul serving as an intolerant slur used to refer to the god of their neighbours. Though it initially had no connection to Satan, by the time of Jesus it had become a nickname for him. Other names like 'Lucifer' are taken from other characters and mistakenly applied to Satan as well.
Incubi and succubi were created by Saint Augustine, he envisioned them as fallen angels who seduced people into sin. Their existence was 'confirmed" later by Aquinas who also thought that the devil was the root of all sin.
The Fourth Laterab Council determined that: "The devil and the demons were also created by God; at the moment of their creation, they were not evil; they became so through their own sins, and ever since they have busied themselves with the temptation of men."
The church began to teach that anything outside of Christianity was a form of Satan worhsip. Whether it was astrology, divination, any rituals belonging to other religions, etc. Naturally this meant that anyone who wasn't orthodix christian was clearly in league with the devil. I probably don't have to tell you all of the horrors that this development justified.
Since the church borrowed dualism from Zoroastrians they eventually took the idea to it's logical conclusion. They came to the "logical" conclusion that if god had innumerable spirits to serve him, and a large organiztion of human worshippers, obviously Satan must have these things as well. So they developed the concept of a large network of Satanic and devil worshippers who were all servants of Satan and were dedicated to destroying gods creations.
At roughly the end of the 15th century two Dominican monks wrote the "Malleus Maleficorum" which was sort of the handbook used for the witch trials. It was a combination of hatred of women, fear of sexuality, and typical religious superstition. Most of the people over the centuries who were blamed of Satan worship, tortured and burned owe it to this book. Though it was actually the civil courts and not the Inquisition that was responsible for most of the trials. The church also taught that Satan could appear as an angel of light. Thus you could be charged with Satan worship even if you claimed to have an angelic vision.
I won't bother with the Inquistion since you probably know it mostly. But after the witch burnings stopped in the late 18th century people still agreed with the general concepts behind the Inquisition. However they came to think that the demon-inspired activity in Europe was mostly within the church itself. So the church started suffering a major loss in credibility.
Some theologians started questioning Satan. They mostly began coming to the decision that Jesus and his disciples drew their demonology from the myths of the period instead of Scripture. The church began to view things like demonic possession as being caused by a force inside of all of us rather than some outside entity. Belief in Satan as an actual entity still exists in the Catholic Church. He's also regarded as an all-evil deity by most fundamentalists and evangelicals. Some of them perceive a Christian believer as always being engaged in a battle with Satan and his demons.
Religious Satanists generally don't recognize Satan as the Christian devil. They view him as a pre-Christian pagan force. They have a code that can basically be described as "Do whatever you want, as long as it casues no harm."
That was long. I'm really sorry taking so much time with that. If you want to know anything else, just ask. But I think I covered a lot. I could also recommend "The History of the Devil" by G. Messandé, and "Good and Evil in Myth & Legend" by A.S. Mercatante. The last one is an older book but much of the scholarship is still sound.
Edit: Apologies for the smileys. Another edit for spelling and a slight clarification.
