The Meritech Clans were a group of nomadic Voidborn pirates and technological scavengers who dominated the Merates Cluster region in the void between the Calixis and Ixaniad Sectors of the Segmentum Obscurus in the waning years of the 40th Millennium. Routinely attacking Imperial merchant shipping in the region between the Calixis and Ixanid Sectors after the clans declared that they had seceded from the Imperium, by 211.M41 their banditry had evolved into an all-out conflict known as the Meritech Wars against the Imperium following the destruction of two Sword-class Frigates of the Imperial Navy's Battlefleet Calixis. After a seventeen-year-long war fought between 211 and 227.M41, Battlefleet Calixis was finally able to crush the Meretich Clans' strongholds. Subsequent investigations by the Inquisition's Ordo Hereticus exposed the hand of the cult of Hereteks known as the Logicians behind the Meritech Clans' secession and assaults upon the Calixis Sector.
Without contest, the greatest danger that the Hereteks known as the Logicians posed to the Calixis Sector was during the Meritech Wars that threatened to destabilise both Calixis and the bordering Ixaniad Sector in the 3rd Century of the 41st Millennium. 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 stellar cluster was dominated by the scavenging Meritech Clans, Voidborn 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 monopolise 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 rumours 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 of the Inquisition, she rallied the defence with merciless intent, purging the Lucid Court on the sector capital world of Scintilla 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 "armoured 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-long 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 manoeuvred their conspirators into highly-placed positions within the logistical effort behind the Imperial response, seeking to profit from whichever outcome might follow. The Inquisition's 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 an Imperial Navy 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 spectre of inter-sector conflict -- had the Calixian Conclave not called upon the authority of the seat of the Inquisition of the entire 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, though the power of this conspiracy has once more begun to spread its shadow across the region.
- Dark Heresy: Disciples of the Dark Gods (RPG), pp. 40-51, 62, 192
- Dark Heresy Apocrypha - Dark Heresy Timeline by Alan Bligh (RPG Web Supplement)
- Rogue Trader: Battlefleet Koronus (RPG), pg. 28