Headcanons: Other Human Kingdoms
I don't think about the others as much as Katolis and Del Bar, but I have a few ideas:
Neolandia is the wealthiest of the human kingdoms, despite most of its area being desert. This is due to having a monopoly on salt production, as well as most of the natural gold deposits in the west.
Most of Neolandia's staples need to be imported--grain and other foodstuffs from Duren, raw lumber from Del bar, etc. Most of their production and exports are luxuries valued across the other kingdoms, such as silk and spices.
The harshness of Neolandia's deserts actually makes them one of the richest remaining sources of magical reagents in the human lands, particularly of Earth, Sun, and Sky primals. Neolandian culture is friendly to magic--mages occupy a de facto place in society comparable to other scholars and intellectuals.
Non-magical sciences are also strong in Neolandia, particularly chemical alchemy and medicine.
Duren is the only human kingdom whose society places emphasis on gender--by tradition, only female-identifying descendants of the royal line may inherit the throne. Women are culturally considered to be more proficient in all spheres than other genders, and are still more likely to occupy positions of high status and leadership.
It is also the only kingdom with something resembling an organized religion. While the ritual worship of the Harvest Goddess has gradually become mostly a cultural feature, there are conservative circles who call for a more forceful return to the old traditions. These groups were responsible for most of the opposition and even assassination attempts against Queen Aanya, with the rationale that the devastating famine during her mothers' rule was punishment from the goddess for progressive cultural reforms they enacted.
In addition to advanced agricultural techniques, Duren has a strong civil engineering infrastructure, particularly with stone. The best stone bridges and roads in the human kingdoms are built by Durenian engineers.
Like Neolandia, Evenere's environment results in unusually high concentrations of magical reagent sources, particularly of the Ocean and Moon primals.
Evenere is also reasonably friendly to magic, but with a slightly different attitude toward the position of mages in society than Neolandia has--Evenerean mages are more mystics than scientists, with layers of tradition and ritual surrounding their practice.
The Evenerean military is mostly a collection of rangers, working alone or in pairs. They are skilled and stealthy scouts, as well as--according to rumor--spies and assassins.
Possibly because of that, Evenerean politics has a reputation of being cutthroat, both figuratively and literally.
And they eat a lot of insect protein. Just saying.