Mechanicum (Novel) - Plot Summary: A Mechanicum prophecy foretells that the Omnissiah will come to Mars during a certain celestial alignment in a very specific way.The Emperor of Mankind arrives "for the first time" on Mars at the prescribed time in the stated manner, and Mars accepts him as the Omnissiah, the physical embodiment of the Machine God.Dalia Cythera, a young menial of the Mechanicum tasked with transcribing Terra’s accumulated knowledge to other data sources, is accused of heresy for her progressive beliefs that technology should continue to advance through innovation, rather than just the discovery of archeotech as part of the Quest for Knowledge.A senior tech-priest of Mars, Koriel Zeth, intervened and brought Dalia to the Red Planet to help her build the Akashic Reader.Dalia proved to have a strong connection to the Warp, which allowed her to make intuitive leaps in logic and understand why a given technology was created, rather than just obeying a series of ritual and ignorant formulations to operate advanced technologies like the tech-priests without understanding the principles behind their function.Dalia succeeded in building the device, a throne-like mechanism which allowed its user to access "all knowledge" by tapping into the power of the Warp. During a test run using the Astronomican to power it, an empath was placed on the Akashic Reader and purported to successfully gain "all knowledge" before their mind was overwhelmed and they died. When the device overloaded Dalia received a sudden vision of something inhuman stirring beneath the surface of Mars.Dalia learned of the "Dragon of Mars" an ancient alien entity defeated in ancient times and locked deep within the subterranean strata of Mars.Dalia pursued her vision to the hope of communing with the Dragon. Upon reaching the Dragon’s prison, she was met by the Guardian of the Dragon, Semyon.Semyon had apparently lived for many thousands of Terran years and was a psyker whose powers manifested with a golden light. Semyon told a version of the events which led to the Dragon’s imprisonment. In this account, the the man  who would one day become the Emperor of Mankind fought the Dragon on ancient Terra and at some point in the intervening millennia had imprisoned the Dragon on Mars.He explained that the Guardians of the Dragon were each chosen by the Emperor. Semyon also explained that the Emperor Himself had laid the foundations of what became the Mechanicum, foreseeing a time when He would need the forges of Mars to become overwhelmingly loyal to Him and His cause.It was the Emperor who had seeded the prophecies regarding the Omnissiah coming to Mars among the antecedents of the present Mechanicum. Furthermore, it is intimated that technologies gleaned from the Dragon served the Emperor's purposes, including the establishment of the Mechanicum.A record of these events, including a work entitled the Grand Lie of Mars, was kept in the Dragon's prison. Ultimately, Semyon passed the mission and the psychic powers of the Guardian of the Dragon to Dalia, indicating that such a transfer had happened multiple times across Human history.  After this transfer, Semyon suddenly aged thousands of standard years in a few moments and his body quickly disintegrated into a golden powder.In the addendum, it is explained that Dalia went on to serve as the Guardian of the Dragon for the next 10,000 Terran years. The Grand Lie of Mars was stolen near the beginning of her stewardship by an unknown party.Meanwhile, tensions on Mars between the tech-priests of the Mechanicum were escalating between those loyal to the Emperor as the Omnissiah and those loyal to the Warmaster Horus.The Fabricator-General Kelbor-Hal felt that the Emperor had unjustly enslaved the Mechanicum to His will using deception to make Himself seem like the Mechanicum's messiah. In truth, the Emperor demanded production for his war machine but offered the Mechanicum no new knowledge in return.In his increasing disgust at the Emperor's attempts to withhold knowledge from the Mechanicum, Kelbor-Hal chose to make a deal with the representatives of Horus: in return for forbidden knowledge locked away since the signing of the Treaty of Mars between the Mechanicum and the Emperor in the depths of Mars, the Mechanicum would pledge its loyalty to Horus against the Emperor.The fabricator-general and his Traitors, soon to be called the "Dark Mechanicum" by the Loyalists, used this forbidden knowledge to transform their followers into twisted, Warp-corrupted reflections of their former selves.Launching a coup d’etat, the Dark Mechanicum released a destructive, Chaos-powered viral scrap code on Mars which infected machinery and cybernetic personnel alike, corrupting their systems and turning them mad, or worse. The scrap code infected cogitator and augmetic systems across the Red Planet and wreaked havoc on many of the Loyalist forge-cities.Learning of the developing civil war on Mars, the Primarch Rogal Dorn, the Praetorian of Terra, despatched a task force of Imperial Fists Space Marines to secure arms, power armour, and other war materiel before it fell into the hands of the Traitors.First Captain Sigismund arrived on Mars and secured as much materiel as he could for the Loyalist war effort, reluctantly leaving the Loyalist Mechanicum forces to fight their treacherous brethren alone while he concentrated on completing his mission.Meanwhile, the Dark Mechanicum, supported by Traitor Titan Legions, finally made their move and attempted to destroy those of their brethren who remained loyal to the Emperor, initiating the all-out civil war remembered as the Schism of Mars.The Loyalists, backed by their own Titan Legions, held out for as long as they could but ultimately chose to destroy their own forge cities rather than allow them to fall into the Dark Mechanicum's hands -- along with all the irreplaceable knowledge and resources contained therein.