The Battle for Southrine Mines and Port Tersius

Segmentum Ultima – Aleph Sector Historical Archive

Entry: 05.025M42

Background: The Gamordal Campaign

By 05.025M42, the fighting between Veers’ Crusade and the Necrons on Gamordal had escalated significantly. This once-minor conflict zone had become a fulcrum of strategic interest for both sides, with the Imperial Crusade forces seeking to establish full planetary control and the Necron dynasties pursuing the reclamation of ancient holdings.

Two critical engagements marked this phase of the campaign—the desperate battle for the Southrine Mines, and the decisive strike at Port Tersius.

The Defence and Loss of the Southrine Mines

The Southrine Mines, located in the mineral-rich southern uplands of Gamordal, had become a key target for both sides. The Imperial defenders, comprising a detachment of House Brascion Knights, were tasked with holding the site against advancing Necron forces believed to originate from the dormant tomb complex beneath the Hasmakep Mountains.

The battle raged for several days as Necron constructs, led by Ophydian Destroyers and supported by Doomsday Arks, engaged in relentless assaults. The Imperial Knights, though vastly outnumbered, fought with honour and ferocity, holding the line through multiple breaches and executing devastating counter-charges.

However, the Necrons’ inexhaustible nature and phase-regenerative technology gradually ground down the Imperial line. By the end of the third day, the Knights were forced to withdraw, ceding control of the mines after suffering heavy losses, including the destruction of two Questoris-class engines.

The Custodes Breakout at Port Tersius

In contrast, the Adeptus Custodes, operating as part of a specialised detachment assigned to Veers’ Crusade, achieved a stunning success elsewhere on the planet. Having been held in reserve near the Imperial bridgehead, the Custodes initiated a rapid strike operation aimed at the coastal settlement of Port Tersius, a location of logistical importance and suspected Necron activity.

The operation, executed with typical Custodian precision, saw the Emperor’s chosen warriors deploying via grav-transport directly into the heart of the settlement. The Necron garrison, consisting primarily of Immortals and Canoptek constructs, was taken completely by surprise.

Within hours, the Custodes annihilated all opposition, employing pyroclastic spears, guardian blades, and superior martial skill to erase the xenos presence. Port Tersius was secured with minimal Imperial casualties, and its capture significantly expanded the Imperial zone of control on Gamordal.

The Southern Campaign on New Cerberex

Segmentum Ultima – Aleph Sector Historical Archive

Entry: 025M42.145

Background: The Escalation of War

As 025M42 progressed, the once-static conflict on New Cerberex erupted into a fully fledged campaign of movement and decisive engagements. The world, once a prosperous Imperial colony before its fall to the Tau Expansion, had become a focal point of strategic importance in the wider Zadoc Subsector War.

For many months, the Dark Angels, operating from their impregnable fortress on Mount Bone, had been conducting relentless raids into Tau territory. These culminated in a large-scale breakout operation in early 025M42, spearheaded by the First and Third Companies of the Chapter, aimed at shattering Tau control across the southern continent.

The Fall of the Southern Continent

The operation commenced with a thunderous assault upon the Angel Plateau, swiftly followed by the liberation of the city of Rideau. The Tau defenders, though initially holding the line with stoic resistance and formidable firepower, were unable to maintain their positions in the face of Astartes precision and brutality.

The Dark Angels moved with characteristic methodical ruthlessness, engaging in a rolling battle that saw one Tau cadre after another eradicated. Their focus was not merely territorial acquisition but the total destruction of enemy assets. By the end of the third week of operations, Tau forces on the southern continent had been completely routed, and the region was declared under Imperial control.

The Northern Surprise and the Loss of Laurier

In the wake of this success, General Van Dorn, coordinating the wider Imperial effort in the sector, landed several Imperial Guard regiments to consolidate the gains. These forces, including elements from the Cadian 143rd, were deployed in the north at Laurier, intended as a northern pressure point against the remaining Tau holdings.

However, the Tau had anticipated the Imperial strategy. Launching a swift and devastating counter-offensive, they struck the newly landed Imperial regiments before they could fully entrench, utilising battlesuit strike teams and orbital drone coordination to devastating effect.

The fighting at Laurier was brief but savage. Caught off-guard, the Guard regiments were nearly annihilated, and by 0505.025M42, the city had been retaken by the Tau, restoring part of their northern front.

The Battle for Albert

The Dark Angels, undeterred, launched a renewed offensive on 1205.025M42, this time targeting the city of Albert, a strategic node linking Tau defence lines across the central belt of the main continent. The Astartes struck with shock and awe, utilising teleportation strikes, Ravenwing outriders, and full-scale mechanised assaults.

The Tau defenders at Albert fought with grim determination, but the weight of the Astartes assault proved overwhelming. Resistance crumbled, and by 1505.025M42, the city of Albert was firmly in Imperial hands.

Conclusion and Strategic Outlook

With the southern continent of New Cerberex now securely under Imperial control, the Imperium had established a unified front from Rideau to Albert. However, the setbacks at Laurier underscored a bitter truth: the Tau remained a dangerous and adaptive enemy, capable of swift retaliation and asymmetric warfare.

Despite their victory, the Imperium still faced a daunting campaign to retake their former colony in full. The northern and eastern regions of the main continent remained under Tau control, and any future advance would likely require coordinated multi-theatre offensives, and careful management of increasingly strained supply lines.

Nevertheless, the victories of the Dark Angels and Van Dorn’s Guard had brought a critical shift in momentum. The reconquest of New Cerberex was no longer a dream—it had begun in earnest.