mmm, sorry for bad english
this is like 1700-1800 era. Something like Pirate of the Caribbean It´s not our world, but with some similarities. It´s a planet full of water, (almost 80% is cover with water, something like Water World, but with some big continents and islands).
There is a Mercantile Alliance, a group of enterprises that get together and create a country. The goverment are all the head of this enterprises, like a congress with a representative, selected between all of them.
To protect all the trips the ships do from one continent to other, they create a military force, actually 2. The Navy, with powerful ships with the aim to protect against corsairs or pirate and the Continental Marines, the foot soldiers and infantry.
There is other country, conformed with people with dark skin (they look like africans). They are agressive, but with strong ethics and are a war culture. But with the difference with our africans, they advance and create a modern society that rivals with the Mercantile Alliance. There are nobles, they are the people that rules the country with the king.
They are tech savys but also use some kind of magic. They navy, are small boat, with porwerful weapon, fast but not too strong against attacks.
They foot soldier work like hunting packs, but modern technology and some of them like magic users (think like special forces)