Prior to the events of the Age of Apostasy Trilla was, as one would expect of a world in Dorvastor sub-sector, a bastion of the Imperial faith and the Ecclesiarchy had a strong influence on the world.  After the Age of Apostasy and the defeat of the Anargo-Dorvastor Alliance the influence of the Imperial Church began to wane, hastened by the increasing influence of the Adeptus Mechanicus on the world.  Those who follow the Imperial faith as espoused by Dorvastor are in fact now in the minority on the world, though those that do are sometimes fiercely protective of their faith and occasionally hostile to those who do not follow the teachings of Dorvastor.  The adherents of the Dorvastorian Imperial Church on Trilla are largely Administratum adepts and lower level workers.  The majority of the population of Trilla either follows the faith of the Adeptus Mechanicus as laid down by the adepts or one of a number of churches that are a mix of the Imperial and Omnissial faiths.

The largest of these mixed churches is the Church of His Iron Benevolence, the symbol of which is an Imperial Eagle overlain with the skull and cog of the Mechanicus and a lightning bolt behind each wing.  The churches of this group always have a large amount of visible metalwork, some functional, some decorative.  The priests wear black robes with varying amounts of red depending on their rank (higher ranking priests have more red on their robes) and carry a staff topped with the symbol of the church, the staff frequently contains a portable sonocaster that broadcasts liturgy when activated, many of the priests have some sort of visible, and not always necessary, bionics.  The teachings of the Church of His Iron Benevolence stress the Emperor’s benevolence to humanity in providing the machines that keep Trilla and the Imperium at large functioning and providing the Adeptus Mechanicus to care for them.  They also view machine spirits, particularly advanced ones as being a bit like lesser Imperial saints, cognisant representations of the Emperor’s divine will.  Though the presence of these mixed faiths on Trilla sits ill with the Cardinals on Dorvastor, who have on a number of occasions persuaded Inquisitors to look into the non-Dorvastorian churches on Trilla, however none show heresy or gross deviancy and given their closeness to the Adeptus Mechanicus all of these investigations have amounted to nothing.

There are some groups within the Dorvastorian Imperial Church in Trilla who greatly resent the dilution of the standard Imperial faith on Trilla and try to return Trilla to the fold of the Dorvastorian faith.  As can be imagined, particularly with the failure of the investigations into the Trillan churches to find anything heretical, some of these groups have tacit backing from the Cardinals on Dorvastor, though they are careful to distance themselves from those groups that use murky means to achieve their ends.