High Lord of Terra

The High Lords collectively form the Senate of the High Lords of Terra also know as the Senatorum Imperialis.

The High Lords are the twelve most powerful officials which represent the most powerful organizations of the Imperium. Officially, they rely upon the Emperor's guidance to inspire their actions. It is they who make the most far-reaching decisions, and who try to direct the overall strategies of the Imperial military. Some Imperial organizations are so important, influential, and powerful that it would be unthinkable for their leaders not to be a High Lord.

The High Lords
The following nine offices are almost always represented by High Lords:  The remaining three positions are most likely to be filled from among the following powerful leaders: 
 * The Master of the Administratum
 * The Inquisitorial Representative
 * The Ecclesiarch of the Adeptus Ministorum
 * The Fabricator-General of the Adeptus Mechanicus
 * The Grand Provost Marshal of the Adeptus Arbites
 * The Paternoval Envoy of the Navigators
 * The Master of the Astronomican
 * The Grand Master of the Officio Assassinorum
 * The Master of the Adeptus Astra Telepathica
 * Lord Commander of the Segmentum Solar
 * Lord Commander Militant of the Imperial Guard
 * Cardinal of the Holy Synod of Terra
 * The Abbess Sanctorum of the Adepta Sororitas
 * Captain-General of the Adeptus Custodes
 * Chancellor of the Estate Imperium
 * The Speaker for the Chartist Captains