Siege of Vraks - The Greatest Obstacle: On 124.822.M41 the 468th Siege Regiment cracked the second defence line, and the floodgates opened. With Krieg forces pushing forward on all fronts, the renegade forces had been forced to retreat or face encirclement and assured annihilation. Recoiling from their positions the enemy forces left behind their rearguards to slow the pursuit and rapidly fell back to the inner defence line, where they could stand and fight again.Encircling the Fortress of Vraks along a front of 150 km, the inner defences was no single line of trenches, but a zone of heavy defences up to 8 km deep. It was thicker again than the previous two defence lines, which had already taken nine years of fighting to be broken. The inner defence line was the oldest and best of Vrak’s citadel’s defences. Ever since Vraks’ founding as an armoury world and the establishment of the Departmento Munitorum storage facilities, the Imperium had been building defences to protect their valuable war materiels. Subsequent planetary governors and Administratum overseers had continually added to the defences with ever more ambitious schemes, and as more and more underground warehouses were constructed, so more defences were deemed necessary.The defences themselves consisted of well-planned and sighted trench lines, bunkers, pillboxes, gun emplacements, hardened artillery firing pits reinforced with sandbagged redoubts and supporting positions. Underneath were labyrinthine bunker complexes and shelters, buried safe from enemy artillery. All had interconnecting fields of fire to turn each approach into a killing zone. As before, the defence line was further protected by belts of razorwire, thousands of tank traps and dense minefields. Unlike the previous two defensive belts, this one was supported by Vraks’ large arsenal of defence laser silos. The defence lasers’ primary role was to protect the citadel and starport from direct assault from orbit. These huge lasers could target and damage enemy spacecraft, but could also be used as heavy artillery on the ground. The defence lasers’ range was such that they could easily engage the Krieg attackers and the defence laser bunkers would be targets for the Krieg heavy artillery, but each had been constructed to protect it from an orbital bombardment, so it was unlikely any land-based artillery would be powerful enough to destroy them. All of this made the inner defence lines a daunting prospect for an attacker. Worse yet, the traitor forces of Cardinal Xaphan had had a decade in which to reinforce them, pre-sight guns and artillery and have every inch swept by fire.Before its sudden fall to Cardinal Xaphan's uprising, Vraks had been considered impregnable. Only the inexhaustible might of the Imperium with its endless resources of fighting men and war-supplies could have considered attacking Vraks' defences head on, and even the seemingly unstoppable war machine of the Imperial Guard had taken the best part of a solar decade, at the cost of 4,000,000 dead (and many more wounded), to batter its way to the inner defence line.Many amongst the 88th Siege Army's high command believed they now faced the army's greatest obstacle. The inner defensive zone had been reinforced and upgraded since Vraks' founding. Beyond it lay the fortress’ curtain wall and within that, perched atop a volcanic outcrop stood the fortress itself, the nerve centre of Vraks. Both were well defended, but they were immoveable obstacles that could be pulverised with heavy artillery. The inner defence line was not a single target and the siege regiments in the front line would have to begin the slow process of attrition and small gains at high cost to eventually breach it. Once inside the inner defence line, they believed the curtain wall and fortress itself would fall relatively quickly.