A ruler assigns ranks to his or her subordinates and hence a ruler may also pick provincial governors. The ruler also acts as governor for the capital city of his or her faction. The sole goal of a ruler is to expand the territory of his or her faction. Only a ruler may choose to declare war or sign a peace treaty.
A governor acts as a semi-ruler of a province. A province must contain at least one settlement. A governor decides what buildings to build in the settlement(s) he or she has under his or her supervision. A governor also collects taxes and pays salaries to the officers under his or her direct supervision. The sole goal of a governor is to administer a part of the territory of a faction and to serve his or her ruler(s) interests.
An officer is a regular faction member who may vote, and who receives a salary, but otherwise has no real power, except over his or her army if he or she happens to be a general. The sole goal of an officer is to serve his superiors, whether that be the ruler or the governor he or she was assigned to. An officer primary plays a supportive role. He or she may be ordered to develop a settlement, or ordered into combat.
A slave is either a former rebel being held captive, or a captured character from a defeated faction.