From Official Wiki of the Renaissance Kingdoms

The council is the institution in charge of the administration of a duchy

Its members are elected for a period of 2 months by all the inhabitants of the villages of duchy during council elections.

The council is chaired by the duke.

It is made up of 11 councilors whose ducal offices is assigned by the duke:

Note that 2 councilors have no ducal offices. The council elections being done by list system, it may be that the duke has councilors from opposing lists, he can therefore take advantage of this lack of offices to put aside 2 possible opponents. But he can also take advantage of this to create two roleplay roles that he considers useful.

Any member of the council can carry out a financial audit of the finances of a town hall or duchy (if he fulfills the necessary conditions).