Lucifer was a fallen angel... there is a difference between fallen angel and demon. Demons are the angels that fell during the first heavenly war. Fallen angels are the angels that fell after the war... Like the watchers when they fell in love with mortal women and created Nephilim.
Now to answer AwakeToLong's Questions:
So then, if lacking free will, how does an angel rebel unless he is instructed to do so?
God did give man a soul and free will.... but he also gave man the ability to choose. The angels were then like "we can choose to do something". As I know it, Lucifer started the war by saying "Why should a son of fire bow to a son of clay". He said this because God wanted all the angels to bow to man. That is the Christian and Hebrew belief.
Hope that helped. Any questions just ask. I am pretty knowledgeable on angelology and angel magick.
Depends... I personally believe it was Archangel Michael only because it was a war between the angels. I mean when humans go to war does God himself deal with them or do other humans?
Lucifer was Satan's name when he resided in heaven as the 'light bearer'. Light referring to knowledge, Lucifer wanted man to be able to acquire knowledge more easily rather than learning it through life lessons as Christians are intended to learn and grow. His desire to fulfill his duties in a more easily manner caused him to challenge the ways of heaven causing the other angels to fight him and cast him out. Michael-'like god' was the one who ultimately defeated him.
Thus, if you come across Satin worshipers or Luciferians, they will most like point towards self knowledge and self growth as their reasoning for their worship of him and not that they are evil or anything of that nature.
Having done some study into Angelology and Demonology, I'll offer a couple of observations.
If memory serves, the "Son of fire" statement is classically attributed to Azazel, and not to Lucifer. Interestingly, Azazel is also known as one of the Grigori who fell significantly after the creation of Man, in the days of Enoch.
Lucifer has also never claimed the title of Satan in any lore that I've seen. You can link that title to Sammael, Beelzebub, and Belial among others, but not to Lucifer -- whose only biblical appearance is in one questionably rendered passage in Isaiah.
"And the great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world—he was thrown down to the earth, and his angels were thrown down with him." Revelation 12:9
