Lucifer/Satan.....

Lucifer / Satan

The name 'Lucifer' means light-bearer, or morning star. (Some argue that the name Lucifer is merely a transliteration of "son of the morning star", and is not actually a name.)

Satan (Lucifer) was a previously beautiful top-ranking angel.

Satan is a created being made by God for good, and began as the highest ranking, most beautiful, and gifted of all the angels. It's not certain if he was actually an archangel or not, but what is certain is that he is a created being that God made.
He was a good angel initially, as were all the angels.

Satan chose of his own free will to twist his purpose, and began to sin and rebel against God.

The initial sins Satan committed was pride, and he felt he should be the most high god, and be the supreme ruler.

The consequence for the actions of Satan was to be cast out of heaven for eternity. (A third of the angels also rebelled and chose to follow him.)

Revelations 12:16
'And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels;
[8] And prevailed not; neither was their place found any more in heaven.
[9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.'

(The remaining two-thirds of the angels in heaven chose to remain good servants of God.)