The Adeptus Mechanicus is an ancient organisation of Tech-Priests who venerate the Emperor in the form of the Omnissiah, the Machine God. They are a strange, dispassionate breed, obsessed with the acquisition of lost knowledge.
The fume-choked forge worlds of the Adeptus Mechanicus pump out a constant flow of munitions, weapons and war machines for the armies of the Imperium.
The forces of the Tech-Priests comprise all manner of ancient, arcane technology; maniples of bionically enhanced Skitarii warriors, Dunecrawlers, robots, battle servitors and bizarre processions of Electro- Priests singing atonal, static-warped hymns of praise to the Machine God.
These armies are sent forth to scour the galaxy for forgotten secrets, and will slaughter anything that stands in the way of their holy mission.