The Nocturnus are based on the Roman Empire

The title "Imperator" was a one of the many titles held by Caesar Augustus, it is also the title held by Ix of the Nocturnus.

In the game, the "Praetorian" are the toughest, basic Nocturnus you battle. In the Roman Empire, the term was derived from the tent of the commanding general or praetor of a Roman army in the field.

The "Hastatus" in the Roman Empire were originally used as spearmen. Which is what the Nocturne Hastatus throw at you.

"Equites" stands for knight in this specific context. In Chronicles, the Equites are the flying Nocturnus.

"Procurator" was known as the second-in-command to the Emperor/Imperator. Which is the title that Shade holds until her betrayel.

And from Greek Mythology:

Scylla and Chayrbdis/Charyb

Charyb was considered a sea monster. And in the game, Charyb's "element" is water.

Scylla, was also a greek mythology monster. And both Scylla and Charyb were always working together to attack their opponents. Just like un the game.

Interesting, eh?