Nice read. Some predictable stuff but the world is interesting.

Before reading reviews here, I completely passed by the whole Codex Alera is a "Romans & Pokemon" fanfic comments. I mean, I see where it comes from and it's funny but that's just surface similarity. I guess Ash – err Tavi – has not yet left Pallet Town Calderon at the beginning. The magic system is more shamanic than just monsters to catch and make them fight.
As for the Roman political system of the land in the text, it changes from feudal/medieval system from Western Europe Middle-Ages often found in other medieval fantastic novels.