The Imperium Government is made up of a council but with the Emperor at the head of it. Members of the council,include First Sword of the Imperium, Herald of the Imperium, Inquisitor of the Imperium, Claw Leader and then ten High Firsts.
External to the Council is the Malazan Administration, which are responsible for the day to day running of the Imperium. They are ones who ensure that the economy is functioning along with infrastructure etc. Though they do it in line with the Council decisions.
The Imperium has operated this way for the last five hundred years, when the Military took on a more dominant role within the Imperium. Prior to this the Imperium was more democratic than today.
Imperium Death Troopers
Unique Military Branches
Inquisition (Controlled by the Inquisitor)