This image of Lucifer is from Dante Alighieri's Divina Commedia, late 15th century.
Lucifer represents the angel of light with individual intellect who 'rebels' against the outside 'dark authority'. This is why he is called the 'fallen angel.' The dark and outside authority can be attributed to our flesh and fleshly desires coupled with the outside material world that attempts to take us away from the true light within each one of us.
Manley Palmer Hall 33° had written in The Lost Keys Of Freemasonry: "When The Mason learns that the Key to the warrior on the block is the proper application of the dynamo of living power, he has learned the Mystery of his Craft. The seething energies of Lucifer are in his hands and before he may step onward and upward, he must prove his ability to properly apply this energy." (page 48)