Lucifer was a former archangel, he led the Blue Blood's revolt against God, condemning them all to walk to earth. He became powerful and discovered he could become even more so by drinking from his own kind- becoming the original Silver Blood. He spread his corruption until Michael send him to hell with his sword.
Bliss Llewellyn is his daughter and she carried his soul... He used her, taking over her body, to carry out his will. He viewed Forsyth as a servant and the rest of the world as cattle, ants, etc. He was Emperor Caligula in Rome. She stabbed herself in the heart with an archangel's blade, expelling Lucifer from herself and sending him back to hell.