The Apostasy Gambit
The Adeptus Mechanicus is the official Imperial name within the Adeptus Terra for the Cult Mechanicus or Cult of the Machine.
In ancient times, before the current Age of the Imperium officially began following the end of the Horus Heresy, it was often called the Mechanicum. The Mechanicus acknowledge the Emperor of Mankind as the ruler of the Imperium of Man, but not the religious truth of the Imperial Cult or the Ecclesiarchy. Instead, the Mechanicus follows its own dark and mysterious scriptures and worships the deity they call the Machine God or the “Omnissiah.”
The Adeptus Mechanicus believes knowledge is the true manifestation of divinity in the universe, and all creatures and artefacts that embody knowledge are holy because of it. The Emperor is the supreme object of worship for Mankind, the living embodiment of the Machine God or Omnissiah, because he comprehends so much, understanding more about the true nature of reality than any other being in existence.
The Adeptus Mechanicus also regard organic flesh as weak and view the removal and replacement of biological tissue with mechanical, bionic parts as sacred. Most elder Tech-priests have few organic parts left and eventually become more machine than man.
The Adeptus Mechanicus is based on Mars, the very first Forge World of the Imperium, and they are the sole rulers of the Red Planet. They provide the technical and scientific experts of the Imperium and field armies of massive Titans, Mechanicus Electro-priests, Skitarii and combat Servitors.
Whereas nearly all the citizens of the Imperium observe the tenets of one of the various sects of the Imperial Cult that worships the Emperor of Mankind as the God-Emperor, the Adeptus Mechanicus is virtually synonymous with the Cult Mechanicus, another faith that could easily be considered heretical by the rest of the Imperium if the Adeptus Mechanicus was not essential to the survival of the Imperium and if the Tech-priests had not proven their loyalty to the Emperor in countless ways.
The Quest for Knowledge
The ultimate goal of the Cult Mechanicus is to understand and fully comprehend the glory of the Omnissiah. The communal and personal attempt at this form of enlightenment is known as the Quest for Knowledge.
The Cult believes that all knowledge already exists in the universe, and it is primarily a matter of time before it can be gathered together to complete the Quest. The Cult is therefore disinclined to perform most basic scientific research and development. Despite this, some original scientific research does continue on Mars and the other Forge Worlds of the Imperium, enough to keep Imperial technology advancing steadily, if extremely slowly.
The faith of the Cult is defined by a series of sixteen precepts, known as the Sixteen Universal Laws, which have been divided into two sets of eight precepts known collectively as the Mysteries and the Warnings, which are listed below: