The Omnissiads' philosophy is considered highly dangerous by its brethren and involves the summoning of the Omnissiah or the Machine God into a pre-built or extensively modified avatar, with the intention of leading the Techpriests in their Quest for Knowledge. While a majority of this group might be united in purpose, their methods of achieving this goal differ.
Some of its members seek the most able of mind-scrubbed Servitors in order to create a perfect host of flesh and metal for the Machine God. Others such as Genetors seek instead to grow monstrous, perfect organic beings in bio-vats. Still others might attempt to create a mechanical construct imbued with dark and forbidden Abominable Intelligence.
To the rest of the Mechanicus, the Omnissiads' actions are reviled, the equivalent of a Puritan Inquisitor associating with Daemonic entities. While this might be the case, there does exist a level of friendship between the Omnissiads and those of similar philosophies, such as the Thorians, Horusians and the Resurrection Cult. Such groups are often sought by Techpriests in order to gain assistance that would allow the Machine God to work in the lands of mortals.
It is because of this friendship that the Inquisition knows so much about the sect and has made secret pacts with the Mechancius to wipe them out in order to prevent their heretical practice of summoning deities. To the Omnissiads themselves, the hour of the Machine God's return seems to be close at hand, with the rise of the xeno-heresies of the Necrontyr, the purging of the Forge World Gryphonne IV and the capture of numerous Dark Mechanicus traitors during the assault against Cadia.