The Hell Warders is a collective made up of a quintumvirate comprised of five Space Marine Chapters, selected by the High Lords of Terra, tasked to defend the Imperium against Chaos incursions from the 'Hellgates', the dual warp storms located in the Segmentum Solar which are located uncomfortably close to Holy Terra.
The area of the galaxy known as Sector Occident Prime is an ancient, populous and wealthy sector located in the Segmentum Solar. This region of space was discovered early on during the Great Crusade in 801.M30, by the Emperor's personal Imperial Expeditionary Fleet whilst pursuing the reptilian xenos known as the Zogrians. Landing upon Zhogun, the second human inhabited world (and the first civilised one) the Emperor led an entourage to the surface to meet with the planet's rulers. Awed by his overwhelming glory, the Zhogune warlords and their vassals eagerly laid their swords on the ground at the Emperor's feet, acquiescing to His glory. The world of Zhogun and its surrounding worlds were brought bloodlessly into Imperial Compliance as part of the burgeoning Imperium of Man, and within one generation the worlds of Sector Occident Prime began fielding fleets and armies to fight in service to Him on Terra.
The Hellgates are a pair of relatively small warp rifts located in the Thermopylae sub-sector, which was once a part of the Loculus sub-sector, but was divided off, following the First Hell Crusade that took place 110-199.M36. These dual warp phenomenon are riven by warp storms so intense that stellar travel in the region is virtually impossible. With the difficulty of travelling through the region, this area of space became a haven to pirates, criminals and Renegades. Within the Hellgates are multiple Renegade Space Marines and various Chaos Warbands. Swirling with warp-energies that permeates its worlds, this region is imbued with the evil energies of the warp which slowly poisons those mad enough, or desperate enough, to reside within.
Located in the galactic core of the Thermopylae sub-sector, together, the Hellgates cover an area of around fifty or so light years across, its presence in space is marked by binary, slowly turning gyre comprised of nebulae, dust and stellar material in which countless vessels and sometimes even worlds have been lost. Though considered a Minoris Grade anomaly, these dual warp rifts still pose a potential risk to the security of the Segmentum Solar as they are located only a 1,000 light years from Holy Terra, rendering them an acute threat to the safety of the Imperium.
Remaining considerably more stable than most other warp rifts, evidence indicates that the Hellgates have been in existence since the evolution of Mankind. Due to their relative stability, the Hellgates have long served as a haven for all manner of renegades, corsairs, outcasts, exiles and other forgotten horrors. These hellish realms are ruled by all four factions of the Ruinous Powers, who constantly vie with one another for absolute supremacy. Many worlds found within the Hellgates' depths have been tainted by Chaos in some way, shaped by the individual wills of their respective masters, while others have been touched by the lapping of stranger tides. The Hellgates are a point of constant interface between the real and the unreal, realspace and the warp overlapping each other like a blurred image. Daemonic incursions and the predations of marauding Chaos warbands are common at the points within the Hellgates where these realities overlap.
The Hell Warders Chapters
The establishment of the Hell Warders Chapter was fully documented in the ancient text known as the Codex Fuego or 'Book of Fire'. According to this ancient text, in 199.M36, following the end of the massive Chaos incursion known as the First Hell Crusade, the High Lords of Terra pronounced an Edict Imperialis in response to the dire predations, ordering several Adeptus Astartes Chapters to permanently base themselves near the Hellgates in order to protect the Imperium's interests and pacify the region.
In recognition of their glorious service to the Imperium, the Golden Castellans were granted the honour of the senior role in commanding the newly formed Hell Warders. As a stalwart Imperial Fists' Successor Chapter created in M33, this fleet-based Chapter had been stationed in the Gathalomor Sector in M36, which put them conveniently close to the action when the First Hell Crusade erupted from the Gates. Leading the Imperial defence of the besieged sector, the Golden Castellans spearheaded the fleet of Battlefleet Loculus against the vast Chaos armada. Utilising their flagship, the Incursus Defensior, a Ramillies-class Star Fortress, this colossus of war utilised its formidable firepower to fight valiantly in many major battles against the Forces of Chaos. This mighty vessel became the lynchpin in the blockade of the Hellgates, playing an instrumental role in turning the tide of the conflict, and driving the Chaos armada back into the swirling eddies of the Hellgates. Assigned permanent overwatch over the twin warp rifts, the newly-renamed Gatekeepers would stand sentinel over the worlds of Sector Occident Prime. Once the Hell Warders were put in place, the Gatekeepers utilised the world of Pylos, building their fortress-monastery, and established the strategically located planet as their base of operations.
The Gatekeepers were also joined by the Knights of the Anvil (or Anvilars), a Chapter of Unknown Founding and uncertain lineage. They are the only chosen Space Marine Chapter out of the five selected by the High Lords of Terra whose presence in Sector Occident Prime predates the First Hell Crusade. This Chapter is known for their skilled artificers and powerful warriors who are dedicated to the adherents of the Fire Cult native to their monastery world of Achaemenia. Their home world is a planet of arid deserts ringed by massive mountain ranges, which are rugged but more temperate in climate than the sun-baked flatlands. The feudal inhabitants of this world are known for fielding the famous Achaemenid Horse and the Mountaineer Foot Astra Militarum regiments.
The collective of Space Marine Chapters was further augmented by the bellicose Spartiate Marines, a 4th Founding Successor Chapters of the vaunted Ultramarines, who hailed from the warlike feudal world of Sparta. The Spartiate Marines had also played an instrumental role in the First Hell Crusade, providing three companies of their Chapter alongside an Astra Militarum regiment of the Laconian Guards to support the beleaguered sector. As one of the first Imperial forces to respond, this force bought precious time for the Imperial defenders to mount a sufficient counter-attack. Focusing all their efforts on superbly devised ranged kill patterns far superior to any that could be conceived, the Spartiate Marines launched ambush tactics that assured an extremely high kill ratio, in which every Astartes traded his life for hundreds, if not thousands, of Chaos heretics.
The origins of this obscure White Scars' Successor Chapter are convoluted at best, as there is no record of them previous to their establishment as one of the Hell Warders Chapters after the First Hell Crusade. However, there are multiple corroborated accounts which date this Chapter back to the 13th 'Dark' Founding, which occurred sometime between M35 and M36. The Lightnings' earliest known battle honours all come from the First Hell Crusade indicating they were a fairly new Chapter indeed, when they were pitched into battle against the Daemon Prince of Slaanesh, Xeraz the Exquisite, and his allies. Stationed upon the feral plains world of Saka, The Lightning launch periodic patrols along the borders of the Sarmatia System, standing ever vigilant for dark portents or other signs of another potential Chaos incursion.
When the Hell Warders were first established, their force included the fleet-based Templars Moline, a Crusading Successor Chapter of the zealous Black Templars. Conflicting reports list them as having taken part in the First Hell Crusade. When the Forces of Chaos launched a massive incursion into the Thermopylae Sector during the First Hell Crusade, the Templars Moline, alongside the Spartiate Marines, were one of the first Space Marine Chapters to respond. However, official records list the Templars Moline as having been created during the 14th Founding in the latter years of M36 - established for the purpose of providing much needed fleet support to the original Hell Warders Chapters. Whatever the truth to the matter, following their permanent assignment to Sector Occident Prime, the Templars Moline established several priory bases in each sub-sector. Their ships maintained a constant vigil, patrolling throughout the sector watching for any signs of Chaotic intrusion. Unfortunately, by the latter years of M41, the Templars Moline were lost during the notable Castigation Crusade in 742.M41, when the Hell Warders and their allies conducted a series of major deep strike operations into the heart of the Hellgates in an attempt to take the battle to their Chaotic foes. When the tides of the warp rifts became unexpectedly turbulent, the rest of the Imperial fleet was forced to withdrawal. Whether the Templars Moline heeded this order or not, is still a subject of much heated debate amongst Imperial scholars. However, much like their Progenitors, the zealous nature and proud martial traditions of the Templars Monline most likely saw them fighting on until the bitter end. They were officially declared 'Lost to the Warp' in 744.M41, and the Bell of Lost Souls was rung back on Holy Terra in remembrance of this lost Chapter.
After the establishment of the Hell Warders Chapters, an Imperial Navy squadron was permanently detached from the Segmentum Solar and permanently assigned to the region to conduct search-and-destroy operations and convoy protection duties. This naval detachment quickly stabilised the surrounding areas and purged the inner zone of the heretical and xenos elements that had plagued them. Soon the wealth of Sector Occident Prime once again began to flow into the coffers of the Imperium. They ensure a permanent blockade is maintained around the Hellgates, and act as a first line of defence should another Chaos incursion erupt from within. In times of crisis, they will often fight alongside the Chapter fleets of the various Hell Warders Chapters or assist them as needed.