Generally speaking, it is agreed that angels do not have freewill, as this was a gift that was given to man alone. It is the reason that we are capable of sinning or living in virtue, and it is this reason that we are judged for our sins.
Angels, therefore, are not capable of acting with freewill or outside of God's design. This then means that Lucifer's "fall" is an act orchestrated by God- the creation of an Adversary, or Satan, so as to more keenly distinguish the difference between life within his light and life without.
Even if Lucifer has fallen, he is still then an Archangel, and arguably still the highest of the angels, as even though the other angels orchestrate God's will it is through the existence of Satan that the goodness of God is most fully illustrated. Never is more light more easily seen than when it is shining in the dark, and other such cliches.
While generally viewed as evil, this reputation is largely born of man's interpretation throughout the mid ages. Satan is barely mentioned in the old testament, with the chief evils spoken of being those where man turns away from God, and virtue. Within the New Testament, Satan is portrayed as he who tempts Christ.
Now, superficially this seems as though it would be a very evil act indeed, but again we must remember that angels do not have free will, an Satan is "the adversary." It is his God-given duty to tempt and test Christ.
This occurs primarily while Jesus is in the desert, alone, and somewhat having a crisis. Satan comes and tries to seduce him from virtue and divinity. Christ rejects this, and returns from the desert stronger in his convictions than he had been before.
You may then argue that God gave Christ the ability to do great good, and the divine spirit to lead men to redemption, and Satan appeared only then to temper Christ's steel, and help him become the man that he needed to be to accomplish what he was going to set out to do.
Certainly this is blasphemous by most interpretations, but it is worth considering, I feel. I do not give much credence to Satanism or anything along these lines, and I am not Christian. But the lessons learned here go far deeper than religious boundaries, and should be viewed outside of the traditional interpretations of men.
