Having established your characters as powerful heroes and champions the RuneQuest Empires rulebook allows them to go one step further, becoming the leaders of peoples and rulers of lands as they seek to raise their banners to strike down all their enemies.
This supplement deals with role playing states, kingdoms or even empires just as if they were a player character, with its own characteristics and skills. It seems quite nice solution and an original approach to rule states in a RPG. Furthermore, brings them close to standard game as it gives the procedure for an ennobled PC to run its own state or manor, with its own funds, problems and so on. Also, how being a high and active member of a kingdom/empire may affect its skills.
The examples for Glorantha, Elric and Rome are quite enlightening.