Battle of St. Klara's Pass

Overview of Events
The Battle of St. Klara's Pass was a skirmish between Space Marines of the Disciples of Dorn and Ork forces of Waaagh! Urtsmog in 825.M41. Codenamed Operation Green Devil by the Disciples of Dorn, the intent of the battle was to eliminate the Warboss of Waaagh! Urtsmog before the group became large enough to threaten the nearby Hive City Invictus Majoris Industrius. The battle was a tactical failure for the Disciples of Dorn, and the emboldening of the Orks by this victory led directly to the First Battle of Invictus Majoris two months later.

Historical Context
The late fortieth millenium saw a steady increase of Ork activity in the Imperius sub-sector. Disparate warbands arrived in the region from the coreward reaches of Ultima Segmentum, pushed out towards the fringes of the galaxy by Imperial operations closer to the galactic centre. These groups posed a headache for Imperial forces in Innsmouth Sector, but the squabbling warbands spent most of their time fighting amongst themselves and only occasionally partaking in small-scale planetary raids of Imperial settlements.

It was the rise of Warboss Urtsmog Dekmaff that turned the Ork forces into a serious threat for the Imperium to consider. Urtsmog came to prominence amongst one of the warbands that had managed planetfall in the wilderness regions of the planet Invictus Majoris in the Imperius Sub-Sector. Urtsmog soon subjugated several other warbands to his control, and the rise of this powerful new grouping actively brought more Orks to the planet. The threat of a serious Waaagh! was now developing, and Imperial forces decided to attempt a decapitating strike before it was too late.

The Disciples of Dorn had been operating in Innsmouth Sector for approximately a century by 825.M41, although most of their efforts had been concerned with defending the borders of the sector against the nearby Tau Empire. A deputation from Ordo Xenos Inquisitor Malfus Tyria and the sectoral division of the Departmento Munitorum approached the Disciples of Dorn and requested them to turn some of their attention inwards to the Imperius Sub-Sector. Although initially reluctant to pull forces off the line, Chapter Master Argoth Tar saw the danger that a large Ork force may potentially cause to their flank and agreed to assist.

Operation Green Devil
The battle plan devised by the Disciples of Dorn was to perform a concentrated pre-emptive strike on Warboss Urtsmog and his retinue of bodyguard units. The plan involved elements of the 1st, 2nd & 4th Companies supported by Venerable walkers from the chapter's Dreadnought retinue. Once the Marines were planetside, they would eliminate the Warboss and decaptiate the Waaagh! before it could even start.

Imperial intelligence appeared to indicate that Warboss Urtsmog was camped with his bodyguard on the outskirts of an abandoned town called St. Klara's Pass. The Disciples determined to drop upon the town itself, hoping to utilise its urban environment for cover and delaying tactics against the Orks.

Intelligence was unavoidably sparse about the bodyguard forces surrounding Warboss Urtsmog. Imperial forces in the area were unable to penetrate the outlying mobs of the Waaagh! to conduct detailed reconnaisance of the Warboss' headquarters. Operation Green Devil therefore presumed a bodyguard force based around highly mobile units with substantial close quarters combat (CQC) capabilities. Operation Green Devil called for a pincer attack, whereby Ork forces would be drawn into an advance against Marine forces and then caught from the rear by Drop Pod assault, thus creating interlocking fields of fire.

Timeline of the Battle
Operation Green Devil began at 2.35pm local time with a successful deployment of Marine forces to the west of St. Klara's Pass. The Ork bodyguard was immediately alerted to the presence of the enemy and swung rapidly into action. As expected, a highly mobile force was immediately organised to attack the Marine forces, headed by none other than Warboss Urtsmog himself.

Marine forces made a cautious advance towards the outskirts of the town, not wanting to close the distance with the Ork mob too quickly and thus eliminate their advantage in mid-range ballistic attacks. However, the Ork forces advanced far more rapidly than the Marines expected, and the greenskins were soon within the limits of the town before the Disciples of Dorn had themselves reached the western outskirts.

At about this time, 1st Terminator Squad from the Disciples' 1st Company deployed via Drop Pod into the rear of the Ork forces. Supported by the Deathwind missiles of the Drop Pod, the squad scored several successful hits against one of the advancing Trukks, which was then finished off by the long-range Lascannon strikes of the main force's Dreadnought retinue. However, the Terminators were then themselves eradicated by a combination of ballistic fire & devastating close combat attack from an Ork Walker. It was at this point the Disciples realized that they had seriously under-estimated the ability of the Ork mob to organise a counter-attack. Ork forces were already on the western outskirts of St. Klara's Pass whilst the Marine forces were only just arriving. Squads were dis-embarked from their transports and readied into positions to return fire at the baying mobs of incoming Orks. This tactial decision was hampered by the destruction of 4th Tactical Squad/5th Company's Rhino transport, blocking their line of sight towards Ork forces advancing through the centre of the town.

Whilst several more Ork vehicles were successfully destroyed by Dreadnought lascannon fire, the Ork advance was yet to be blunted. Several strikes against the Dreadnought retinue left them damaged, whilst 7th Devastator Squad/2nd Company suffered injury following a Plasma Cannon overload in the heat of battle. This was followed by Ork ramming actions that further damaged one of the Dreadnoughts and resulted in the destruction of its Storm Bolter.

Facing a close-quarters assault that they were ill-prepared to receive, Marine commanders ordered a tactical withdrawal before their forces were overrun. This caused some protest from Inquisitor Tyria, which was resolved only after coming to near-blows with Marine Captains Oberdier Langstrom and Alex Sturm. Eventually however, the Inquisitor was persuaded that the unneccessary deaths of valuable Astartes assets for the sake of pride was a tactically unsound decision. General Withdrawal was ordered at 6pm, bringing the battle to a close approximately three-and-a-half hours after it had begun.

The Disciples Chastened
The defeat at St. Klara's Pass was a damaging blow to the equipment and morale of the Disciples of Dorn. Chapter Master Argoth Tar himself undertook an investigation into why the battle had been lost, resulting in the censure of several senior Marine officers & tacticians. The investigation concluded that there had been a lack of effective consideration for weapon loadouts, battlefield positioning, and the capabilities of the enemy. The 2nd & 4th Companies were proclaimed "Chastened & Indebted", requiring them to undertake penance for their mistakes by concentrating all of their efforts on the destruction of Waaagh! Urtsmog.

The Orks Emboldened
The defeat of Space Marine forces at St. Klara's Pass resulted in Warboss Urtsmog consolidating his position as the strongest Warboss in the sector, allowing him to point to a victory against a major armed opponent. This emboldening resulted in the further growth of his warband through subjugation & annexation of even more Ork groups, until two months later when Urtsmog officially declared his Waaagh! and engaged Imperial forces at the First Battle of Invictus Majoris.