What Ende is to land war, Etmarch is to the sea. Their location as last/first port of call for the returning trade fleets has made their island rich, but unlike the other islands, control of that wealth has stayed firmly in the hands of the King, the nobility, and the merchants are kept strictly under control, with much of their profit being diverted to state coffers. The monarchy is all powerful in Entish society and rules as almost a complete tyrant, albeit generally a benevolent one.
Unlike the other islands, Etmarch has focused primarily on deepwater ships and deepwater sailing. Due to the distance that separates it from the other islands and the relatively fierce weather of the Etish Sea, galleys have proven impractical. Their deepwater navy and its sailors, while small, is top notch and they have a reputation of building the best ships outside of Haven, though they cannot match Haven Galleons for shere size of vessels.
Culturally, Etmarch is almost pure Annish, they relish and celebrate their culture, still speak old Annish at occasions of high significance and think of themselves as true descendants of old Ann.
Inspiration
In addition to the same 17th century Caribbean inspiration of the overall The Thousand Isles, Etmarch is inspired by the 17th century Dutch and English.