Each player selects a nation to play.
Any nation from the Warmaster rulebook can be chosen and the same nation can be played by more than one player.
Each nation has it's own nation table showing the markers player's choosing that nation get at start and what markers they can recruit on the different kinds of terrain.
There are nation tables for Empire, Undead, High Elves, Chaos, Orc & Goblins, Dwarfs, Bretonnians and Kislevites.