Are the Illyrians a Retired Prototype of the Angels from Crescent City?
Illyrians are notorious throughout Prythian, because they are only found in Illyria and because of their physical appearance, most notably their bat-like wings. While bats are commonly believed to be nocturnal (most active at night), they are actually crepuscular (most active at dawn/dusk).
Why is this important? This creates a link between the Illyrians and the Dusk Court, the Court that has been destroyed for all purposes and now serves as a Prison, but has some strange link to CC. We know this because the Asteri have a literal room called Dusk's truth, that mentions an island (the Prison) in another world (Prythian) where the fae in CC came from. The floor in the inner chamber of the Prison also has an eight-pointed star engraved into it, the symbol of the Starborn fae in CC.
Their geographic spread is also a little strange. The people of the Dawn Court and Drakon's people have the same feathered wings, so their population spread sometime in the past, and many other species are mentioned to be found throughout the world, but Illyrians, for some reason, stick to their mountains.
The Illyrians also have Ramiel, which they believe to be a sacred mountain and is essentially a giant teleportation machine. They also have stories of their greatest warrior protecting the pass, and stopping people from getting to the top, where the a strange black stone is, so we know it served an important at some point in history.
It is possible that Ramiel somehow acted as a portal, or at least a small window, that the Asteri could control and used to send the Illyrians, soldiers they had created for conquest, into Prythian, since they obviously had some issue with the people of Dusk.
If I remember correctly, CC mentions that the Starborn Queen Theia, who is presumably from the Dusk Court, created problems for the Asteri, so it is possible that in return they made Illyrians to fight for them in Prythian, but when Theia somehow removed their access to Prythian, the Illyrians were left behind, with protecting Ramiel programmed into their brains, and the Asteri created new and improved soldiers for Migard, who were more obedient and had better healing.
