Lucifer isn’t a demon to begin with. He’s the Latin translation of the Hebrew word “helel”. In both cases it’s a poetic nickname for the King of Babylon, not the King of Demons.
See exhibit A: St. Lucifer of Cagliari, a pre-Latin Vulgate Bishop.
Lucifer is a minor deity in the Greco-Roman Pantheon, being the Roman (and therefore Latin) version of Heosphoros, God of the Morning Star (Venus). And Lucifer certainly isn’t the most powerful Greek God.