#i.e. Lucifer Superbiae

[canonlucidia]

Simplified Demonic Hierarchy: 

King Diavolo (Current)  Queen Consort Royal Consorts Heir Apparent Diavolo

Cardinal Sins (Superbiae, Avāritiae, Invidiae, Īrae, Luxuriae, Gulae, Acēdiae)

Dukes, Duchesses, Duchies, (Past Kings and their consorts are demoted to this rank) (Non Heir Apparent) Princes, Princesses, Princexes

Marquises Counts, Countesses, Countexes Viscount, Viscountesses, Viscountexes

Baron, Baronesses, Baronies Lords, Ladies, Lieges

Notes:

Titles are initially gained through either heredity or level of power, although they can be given and rescinded by either the King or the Heir Apparent at will

The Cardinal Sins are chosen by the current king as his advisers, usually upon his ascension. The current line up (Lucifer, Mammon, Leviathan, Satan, Asmodeus, Beelzebub, and Belphegor) were chosen by [prince] Diavolo’s father, as the previous Cardinal Sins all perished in the war with the Celestial Realm. They are ranked by power, but not always in the same order. In the previous Cardinal Sins, Īrae, or Wrath, was first.

Barbatos is technically a Duke