Government: Gone. The Monarchy is dead; some surviving leaders are in Helia now as local lords. Previously it was feudal system similar to Helia, though more centralized and far more dour and socially divided.
Economy: Serenac had some of the best farm land in the world and most of economy was based on large-scale plantations owned by the elite. These plantations were worked by the peasants. Taxes were high in order to fund a rather large and ornate military based upon mounted nobility as heavy infantry.
Serenac had a focus on honor and pride, along with a tendency towards violence, that led it to be seen as one of the more violent countries in the south. In fact, prior to the tragedy of the Landfall War, they were often disliked as a nation.