In Stellaris, feudal society is a type of government that is based on a hierarchical system of lords and vassals. The ruler of the empire is the highest lord, and they have the power to grant titles and land to their vassals. Vassals are expected to provide military service and other services to their lord in exchange for the land and titles they receive. The vassals are also expected to pay taxes to their lord, and in return, the lord is expected to provide protection and justice to their vassals. Feudal society is a very rigid and hierarchical system, and it can be difficult to change or modify it.
