Beseritor is a Hive World located within the Jericho Reach. Its conquest was one of the last great successes of the Achilus Crusade in the Orpheus Salient before the crusade's first encounter with the Tyranids of Hive Fleet Dagon.
When communications with the Imperium ceased at the dawn of the region's Age of Shadow, Beseritor's sudden growth and development came to a screeching halt. Civil wars broke out, as various factions vied for control in the power vacuum left behind.
Construction on the partially completed hive city was abandoned. Initially the manufactoria and mines were strategic assets, but they were soon turned into dangerous ruins where survivors dwelt.
As the millennia passed, the population fell further from the technological standards of Imperial civilisation. By the time the crusade made contact, the planet's once-thriving civilisation had been reduced to little more than warring city-states made up of subsistence farmers whose most advanced technology was coal-powered steam engines.
Though a few of these cultures still remembered the ancient legends of the God-Emperor, the majority had fallen prey to heathen nature worship.
With the assistance of the newly converted, General Mikal Curas chose to use overwhelming force to make examples of the resistant city-states. After the second city was laid to waste, the remaining resistance elements surrendered.
The general quickly pronounced the system Compliant, and brought in the Tech-priests of the Adeptus Mechanicus to begin reconstruction. To everyone's surprise, many of the Imperial ruins, including the partially-completed hive city, were salvageable, even after having been abandoned for millennia.
No explanations for this unusual state of preservation have been offered. In a matter of solar weeks, construction was resumed, and the process of relocating the population to the new hives was begun.
In short order, the manufactoria belched smoke once more and the planet began tithing its due to support the crusade. Today, the planet's single hive city is thriving, and construction on a second hive has begun.
As the Tyranid incursion has continued, the Orpheus Salient has becoming increasingly reliant upon Beseritor's production. The manufactoria have been pushed to capacity, and ancient mines are being examined for viability. Some members of the Adeptus Munitorum have even begun to argue that it may already be time to raise a Beseritor regiment.
Because of this success, several light Imperial Navy vessels, designated Battlegroup Vishnu, have been assigned to keep station over the system. Communications between the system and the command elements of the Orpheus Salient have recently become restricted, as the Shadow in the Warp has encroached.
Similarly, there have been some difficulties in maintaining consistent supply lines from the planet. Many fear that were it not for the presence of the battlegroup, this breakdown could offset the recent progress, causing the system to slip once more into anarchy.
Beseritor is within a short Warp voyage of several systems currently under attack by Hive Fleet Dagon. This proximity has enabled it to serve as a rally point and resupply station for elements directly involved in the fighting.
Oddly, no Tyranid incursions have been seen in the system. Rather than question this absence, the command elements of the salient have chosen to graciously thank the Emperor for His protection and exploited the resources at hand.
- Deathwatch: The Achilus Assault (RPG), pg. 58