Just as Archangel and Angel , Dominions, Principalities, and Powers are in heaven, so it is said demons and devils are in hierarchy of hell, Princes, Ministers, Ambassadors, Justices, The House of Princes, and the Trivial Spirits, Alphonsus de Spina (who brought into Christianity a lot of Jewish lore) says there are ten orders of demons. Some other authorities say there are nine orders of devils, some six, some four.
This was an idea that was especially appealing to the hierarchical mind-set of the Middle Ages. At the top is God's Adversary himself, Satan. At various times he is confused with Lucifer, The Angel of Light, The Prince of Darkness, The Dark Angel, and others but it is Satan we usually mean when we speak of The Devil. All others are demons, not devils, though our language tends to regard devils and demons as synonymous.
Here are the principal personages in the infernal kingdom, in alphabetical order, because there is some disagreement about their exact placement.
What is more interesting than that, however, is how it is imagined that the kingdom of hell mirrors other kingdoms. It is also interesting how and why students of demonology hit upon the very specific numbers of infernal legions commanded by this or that power.