New Cerberex: Dark Angels continue breakout

By early 025M42, the once dominant position of the T’au Empire in the Mabb Nebula had begun to unravel. Just a year prior, the T’au had been poised to establish a Zadoc Expansion Sphere, having secured New Cerberex, launched an invasion of Hylas, and maintained a tense but stable front against Chaos on Zadoc itself. However, as the war expanded across the Zadoc Subsector, it became clear that the T’au and their Federal allies were overextended.

While the T’au had defeated the Imperial fleet and enforced a blockade within the Mabb Nebula their grip on the subsector was not absolute. Astartes fleets, refusing to engage in pitched battles, continued to operate freely, slipping past T’au naval patrols to deploy reinforcements and supplies. The T’au and their allies simply lacked the naval coverage to maintain control over three major war zones simultaneously—the Perseus Deeps, the Hadron Expanse, and the Zadoc Subsector. Seizing upon this weakness, General Van Dorn, now commanding the Imperial war effort in the Zadoc subsector, exploited the overstretched enemy. His offensive on Hylas forced the T’au-Federal alliance to divert precious resources, further weakening their defensive hold over New Cerberex.

Despite the T’au’s claim of having secured New Cerberex, they had never eliminated the Dark Angels or breached their fortress monastery on Mount Bone. Recognising the fragility of the T’au position, the Dark Angels Chapter launched a devastating assault in 01.025M42, striking from their stronghold on Deathwing Ridge. With speed and precision, the Astartes descended upon T’au defensive positions at Vincennes and Albert, their rapid-strike doctrine overwhelming the surprised defenders. The T’au attempted a counter-offensive, but their forces were soon bottled up in Albert, unable to manoeuvre effectively against the fast-moving Space Marine formations. With their defences shattered, the T’au were unable to prevent the fall of Vincennes, a vital settlement that cut their forces in two.

Despite this setback, the T’au still controlled the key strategic locations on New Cerberex, including New Feducia, New Grasx, and the spaceport, but the notion that the world had been fully integrated into the T’au Empire was crumbling. The Dark Angels’ lightning assault proved that the Imperium could still contest the world, and the illusion of T’au security was shattered. Now, the T’au-Federal alliance found itself fighting on two major fronts in the Zadoc subsector—against Van Dorn’s renewed offensive on Hylas and the Dark Angels’ resurgence on New Cerberex. With the war effort stretching their resources thin, the T’au’s grand ambitions in the Zadoc Expansion Sphere were beginning to collapse under Imperial pressure.