Master of the Administratum

The Master of the Administratrum is the High Lord of Terra who serves as the top official of the Adeptus Administratum, the governing bureaucracy of the Imperium of Man. The individual who ascends to this rank is always one of the nine permanent members of the Senatorum Imperialis. The Master of the Administratum is also the titular head of the Departmento Munitorum which handles all of the logistics of the Astra Militarum, though in practice he or she must also share influence over that bureaucracy with the Lord Commander Militant of the Imperial Guard and other high-ranking Imperial military officers. At least in name, the Master of the Administratum is perhaps the most powerful man or woman in the galaxy, as they control the portion of the Imperial government that is most crucial in the day-to-day functioning of an interstellar state -- its bureauracy. In truth, the Master of the Administratum handles none of the day-to-day affairs of bureaucratic governance; the role is primarily concerned with ceremony, public relations and the constant political infighting which generally consumed the High Lords of Terra before the return of the Primarch Roboute Guilliman as ruling Lord Commander of the Imperium in 999.M41.

History
In the wake of the Horus Heresy, the Reformation of the Imperium initiated by Roboute Guilliman during his first stint as Lord Commander of the Imperium created the Adeptus Administratum by officially aggregating all of the various Imperial military and civilian bureaucracies created under the auspices of the original War Council and Council of Terra during the Great Crusade. By its very nature, the Master of the Administratum emerged for the first millennium of Imperium's history as the most politically powerful office of state, as long as that state remained officially secular in character. After the emergence of the Adeptus Ministorum as the official state church of the Imperium in the middle of the 32nd Millennium, the Ecclesiarch who lead the faith overtook the Master of the Administratum as the most powerful among the High Lords of Terra in practice. This culminated in the 36th Millennium during the Age of Apostasy with the rise of Goge Vandire, whose use of assassins and the manipulation of Ecclesiarch Paulis III ultimately allowed him to become both the Master of the Administratum and the Eccleisarch of the Ministorum, threatened to transform the stable theocratic oligarchy the Imperium had become into a true dicatorship. His assassination at the hands of Alicia Dominica and her Brides of the Emperor ended this threat to the realm. The Adeptus Astartes and the Inquisition's newly formed Ordo Hereticus dismantled the overweaning military power of the Ministorum and restored a balance between the Administratum and the Ministorum that lasted more or less intact until the return of Lord Commander Guilliman in 999.M41.