This Game Takes place in the Dune Universe, where Each player is the Ruler of a powerful Great House:
What is A Great House, and what are its duties?
The Emperor of a million worlds cannot be everywhere at once, neither can his Legions of Sardaukar Super-soldiers. That's where Great Houses--you-- come in. Depending on their personal history, Every Family has earned, bought, stole, usurped or was otherwise granted noble status. By becoming a noble (Duke, Marquis, Earl, Count, Viscount, Baron, etc.), and by having a decorated family history, you are given or inherit leadership of a Family with influence and governorship (also called Siridarship) of your own planet, or in other cases, several planets (calld "Fiefs") and other Holdings.
As a governor/siridar as well as leader of your House, your job includes:
I: Oversee your planet(s), create goods to the uber-corporation CHOAM, for profit, as well as for other customers from other Houses.
II: Represent (or have an ambassador do it for you) your House in Landsraad Congress, in the Presence of the Emperor, or at CHOAM headquarters, all on Planet Kaitain, the Imperial Capitol.
III: Protect your Holdings, Civilians and Family from the enemies you're bound to collect sooner or later.
How you do each is your business.