How does magica work ?

[Enkidoh]

That doesn't hold weight I'm afraid, seeing as here states Garlemald's origins as a Hydaelyn-native 'insignificant nation' in the northern part of Ilsabard, and only with a sudden technological revolution did they spread out into the wider world:

Until some fifty years ago, Garlemald was a remote and sparsely populated nation which held little more than a fraction of the northern continent of Ilsabard. But with the arrival of a technological golden age and the concurrent emergence of a brilliant young legatus—now the reigning emperor—in the span of a single generation Garlemald established itself as one of the most formidable forces in all of Hydaelyn.

Native Garleans are just hyur who have a third eye, which, although it's unconfirmed, to me resembles more an implant rather than an actual natural optical organ. It rings true that a people advanced in technology (and especially magitek), would also be skilled in cybernetics. But only a certain ahriman knows for sure.