The Imperial State is run by a vast and extremely comprehensive bureaucracy which employs some quarter of the Empire's 1.2 billion people in some capacity.
Her Sovereign Majesty's Armed Forces Ordnance Corps[]
The Ordnance Corps is the agency responsible for supplying the armed forces of the Empire. It is one of the largest components of the Imperial military, with a vast and complicated system of sub-agencies and departments. One of the most important functions of the Ordnance Corps is the supply of Patterns for factories. In essence, a Pattern is a piece of equipment, produced to exacting standards, which is then shipped to a particular factory that fabricates replicas of it en masse for general deployment. This has led to calling models of particular equipment by Pattern, e.g. "Type 4219 Long Land Pattern Rifled Infantry Musket" for the rifle-muskets used by Imperial Line Infantry. (The Term "Type" does not indicate sequence, i.e. the current Type of Line Infantry Rifle Musket is not the 4219th iteration, but rather it denotes the Imperial Calendar Year, which is based on the Empire's founding. So Type 4219 means that the first Pattern for that particular piece of equipment was crafted in the 4219th year of the Empire's existence). Each factory has its own Pattern for each piece of equipment it produces, and every single thing which that factory produces is approved by the Ordnance Corps before being shipped to its designated army. Each Legion also has a large staff of Ordnance Corps personnel to manage its supplies and run its Legion Depot. The Ordnance Corps is notable in that more than half of its personnel are female. The head of the Ordnance Corps is called the High Magister of Ordnance, and is one of the members of the Imperial Grand Council (the 'cabinet' of the Arch-Chancellor of State, the Empire's elected Head of Government).
Her Sovereign Majesty's Army Staff Corps[]
The Staff Corps is the administrative and operational control organ of the Imperial Army. Every Legion has a cadre of professional staff officers who are attached to the various levels of command, from Battalion level to the Legate (usually with the rank of General-Major) who commands the Legion in question, and also to the Marshals in command of Armies and Army Groups. The Staff Corps is responsible for the command and control of the entire Imperial Army, its planning and the execution of said plans. Staff officers formulate plans of action as well as ensure they are adhered to and carried out. They work closely with the Ordnance Corps and provide for the logistics and supply, reconnaissance, operational control and communications of Imperial forces. They are, in essence, the "nerves" of the Imperial war machine. The highest organ of command and control in the Imperial military is the Lords Marshal, a council of 12 Marshals who have recieved the appointment (not rank) of Lord Marshal personally from the Empress and serve as a Supreme Command controlling the entire Imperial military. The Lord High Marshal, appointed directly by the Empress from among the 12, is the head of the Lords Marshal and is also a member of the Arch-Chancellor's Grand Council, though he reports to directly to the Empress on military matters and is only responsible to the Arch-Chancellor in part, on the confidence of the Empress (to whatever degree she determines).
The head of a particular Imperial officer's Staff has the right to appeal to a higher authority and circumvent the competency of said officer where operational matters are concerned. However, this carries a heavy weight of responsibility, as an appeal that is found frivilous or in bad judgement will reflect badly on said Staff Officer. More than one Staff Officer has lost his or her position for failing to trust in the judgement of his commander. The Staff Corps is another organization notable for employment of women. It is also instantly recognizable for its créme-colored uniforms which, unlike almost all other Imperial uniforms, do not reflect either a color on the Imperial flag (black, red, pale blue and white) or the Empire's "royal" color (maroon). Note that there are many officers on a given commander's staff who are not members of the Staff Corps and handle other responsibilities besides planning. The Staff Corps has no single leader or directing body and is an integral part of the Imperial military, subservient to the Lords Marshal and the Empress.
Imperial Magistrate[]
A Magister is a functionary of the Imperial government with administrative authority, and the term Magistrate is used to refer to the Imperial Government itself. There are a vast range of Magisters, all fufilling some Civil or Judicial function. In essence, the Magisters run the Empire's bureaucracy and by extension, the Empire itself. A Magister is not just any government offiicial, however - the title carries with it significant authority. A Magister is usually the head of some type of office at some level of government or fufills some important function. For example, the local tax collection offices and railroad commissions are all headed by Magisters. Magisters govern Imperial Prefectures (non-federated provinces within the Empire controlled directly by the Imperial government). Often Magisters have some other, more specific title (i.e. the Magister who governs a Prefecture is called a Magister-Prefect, but more commonly just Prefect). All Magisters have the authority to call upon the support of the Imperial Constibulary, (the Imperial Guardsmen, a combination Military Police and government-controlled "federal" police force). The Magisters ultimately are under the authority of the Arch-Chancellor of State himself (or herself).
One of the most distinct roles of Magisters comes through the Imperial judicial system. Criminals are tried by a tribunal of twelve Judicial Magisters acting as judges, with the help of a jurry. Unlike in the real world's English Common Law system, however, it is this collective organ of Magisters, not the jurry, which pronounces the sentence. The jurry is simply there as an advisory body, and is usually made up of various minor government officials (often Magisters themselves, but never Judicial Magisters).