The Adeptus Mechanicus is a technological organisation, often known as the Priesthood of Mars. It holds a monopoly on technological knowledge in the Imperium.

Their Forge Worlds turn out the Imperium’s most powerful and advanced weaponry and equipment.

The organisation’s adepts, the Tech-priests, are vital in maintaining much of the Imperium’s more technologically advanced equipment, not the least of which is the Emperor’s life-sustaining Golden Throne.