Without contest, the greatest danger that the Logicians posed to the Calixis Sector was during the Meritech wars that threatened to destabilize both Calixis and the bordering Ixaniad Sector some six centuries ago. The Merates Cluster is a grouping of a dozen barely habitable worlds caught in the empty void of space between the two Imperial sectors, claimed fully by neither and largely considered more trouble than it is worth. The cluster was dominated by the scavenging Meritech clans, void-born families who maintained ramshackle caravan fleets that plied the space between the sectors, mining, trading, salvaging, and fighting off attacks by corsairs and marauding Ork vessels as best as they were able. Over the years the clans grew stronger and began to monopolize much of the border trade between the two sectors, and the size and sophistication of their fleets grew to be a serious concern to the local authorities. Unfortunately, other crises and events pressed and the matter was left to fester.
It finally came to a head when a Battlefleet Calixis patrol squadron of frigates pursuing suspected pirate activity in the cluster were ambushed. All but one frigate was destroyed by clan warships---the Merates Uprising had begun as the clans seceded from Imperial rule. The Meritech clans quickly took an aggressive stance and launched scores of raids and strikes deep into both sectors, causing widespread panic and discord. Their vessels were small, but their advanced jamming systems and compact yet powerful weaponry made them more than a match for their Imperial Navy counterparts. In addition, their boarding parties were made up of heavily cyber-augmented shock troopers that smashed through the Imperial opposition with ease.
For a time the whole Calixis Sector reeled with the shock of the Meritech assault and several worlds threatened to fall into civil war as rumors of the rebellion spread. While the powers of Ixaniad bickered and withdrew to defend their own borders, a newly enthroned Sector Governess took charge in Calixis. With the backing of the Calixian Conclave, she rallied the defense with merciless intent, purging the Lucid Court of dissenters and rivals in a single bloody night. Her plan, rather than fruitlessly chasing a hundred smaller threats, was to simply and mercilessly strike a blow from which the enemy could not recover. Regis Sectora Myram Harvala, in what is remembered to this day as the Proclamation of Scant Mercy, ordered the Sector Battlefleet to mass into an “armored fist” and smash directly into the heart of the Merates Cluster. With the might of her armies pouring in behind, no pity, quarter, or mercy were given to any found there.
As the seventeen year purge of the cluster went on, Inquisitorial investigations revealed that the Logicians had been both the instigators of the crisis and the source of the clans’ newfound technological might. It appeared they viewed the war that had cost millions of lives as little more than a massive series of field tests. The Logicians had maneuvered their conspirators into highly placed positions within the logistical effort behind the Imperial response, seeking to profit from whichever outcome might follow. The Holy Ordos’ wrath was terrible, and in conjunction with the Mechanicus faction known as the Divine Light of Sollex, they systematically hunted down and scourged the Logician influence from Hive Tarsus on Scintilla, Fenksworld, and dozens of other commercial operations and military vessels where it had taken root.
In the latter stages, much of the Merates Cluster was laid waste as a task force hounded the remnants of the Meritech clans and their Logician masters deep into the Ixaniad Sector, causing a major diplomatic incident and conjuring up the specter of inter-sector conflict---had the Calixian Conclave not called upon the authority of the seat of the Holy Ordos of Segmentum Obscurus to intervene. In the aftermath of the Meritech Wars, it seemed that the power of the Logicians in the Calixis Sector had been broken, and so it remained at least for several centuries.
A thorough Inquisitorial investigation was conducted after Sector Governor Harvala declared the rebellion at an end. While laudable, the brutal zeal with which the forces of the Imperium, and the Adeptus Mechanicus in particular, had conducted the final phases of the counter-attack, had left not a single witness or prisoner to be questioned or paraded before the victorious processions along the avenues of Scintilla. Even those prisoners who had been taken prior to the arrival of the Mechanicum’s elite Crimson Guard were eventually lost to a rash of unusual malfunctions and sudden, mysterious deaths.
The Inquisitors exhausted all possible avenues of inquest, and soon followed whispered rumors of the Logician Tech-Heresy to the very doorstep of the Lathe System itself. However, rather than cooperate with the forces of the Governor, Fabricator Davos Phar responded with a brittle show of icy indifference, imperiously dismissive of the envoys’ requests, and accused the Inquisitors, their masters, and the very Sector Governor himself of blatant disrespect and towering hubris. Referring to them as “the miserable curs of a thankless master”, the Fabricator ordered the frontiers of the Lathe System and all other Adeptus Mechanicus holdings in the Calixis Sector closed, and all the force at the Fabricator’s disposal was bent to keep outsiders from penetrating the sovereign territory of the Omnissiah. The ancient Iron Wall of Silence was re-instituted, and stood again unbroken for over five hundred years with brief exceptions, until the Malygrisian Tech-Heresy erupted across the Calixis Sector, forcing the Adeptus Mechanicus once again into the affairs of the Sector at large.