The Setback at Vincennes: Dark Angels Ambushed on New Cerberex

For much of early 025M42, the Dark Angels had appeared an unstoppable force on New Cerberex. Launching raids and assaults from their fortified stronghold atop Mount Bone, the First Legion's operations had transitioned from guerrilla strikes to an all-out campaign of planetary reconquest. With only a single Astartes company, the Dark Angels had wrought devastation upon Tau installations, taking settlements such as Vincennes and dividing the xenos occupation zones.

The Tau Empire, still stretched thin across multiple fronts from Zadoc to the Hadron Expanse, had been unable to effectively respond. However, in late 03.025M42, the xenos struck back with unexpected precision and speed.

Utilising stealth technology, local Federacy intelligence assets, and mobile Hunter Cadre units, the Tau launched a coordinated counteroffensive against the Dark Angels' garrison at Vincennes. The attack, executed with uncharacteristic cunning, saw the Astartes force encircled and cut off from reinforcement or retreat. By the time the Dark Angels became aware of the trap, the noose had already closed.

The ensuing battle was fierce and unforgiving. Though the Dark Angels fought with grim resolve and inflicted heavy casualties upon their attackers, the xenos had the advantage in numbers, position, and tactical preparation. The entirety of the Vincennes garrison was eventually overrun, the city retaken by the Tau, and the Imperium’s momentum on New Cerberex abruptly halted.

This marked the first significant Imperial defeat on New Cerberex since the Dark Angels' campaign began, and raised serious questions within the Imperial command hierarchy. The notion that a single company of even the Emperor’s finest could single-handedly reconquer an entire world from the Tau-Federal occupation now seemed overly ambitious. Though Mount Bone remained inviolate, and the Dark Angels still possessed the capacity for future strikes, the days of unchecked advance had ended.

The Tau, emboldened by their success, began reinforcing positions in the central continent, wary now of further Imperial action. For the Imperium, and General Van Dorn, this reversal was a sobering reminder that while Astartes were the sword of the Emperor, even they could bleed and falter when outmatched by planning, subterfuge, and sheer attrition. The war for New Cerberex was far from over—and it would no longer be won by boldness alone.