An Enginseer, also called a Tech-priest Enginseer, is a Tech-priest of the Adeptus Mechanicus whose specialisation is the maintenance and repair of the many technological instruments of the Imperium of Man, both in peace as in war. Enginseers are engineer mystics, members of the Adeptus Mechanicus who are dedicated to the Machine God and steeped in arcane knowledge. Enginseers are the most commonly seen members of the Mechanicus, for they are present wherever a somewhat technologically advanced human settlement resides. By virtue of the ancient Treaty of Mars, many Enginseers are attached to the Astra Militarum and Imperial Navy, maintaining and repairing the Imperium's vehicles, aircraft, starships, and other wargear and ensuring that the warriors who prosecute the Emperor's wars always have the means to do so. These cybernetic holy men stand aloof from the Imperial Guardsmen, concerned only with tending to the Machine Spirits of their foster regiment's many vehicles and weaponry.