Badab War - The Maelstrom Zone: Situated along the Eastern Fringe in the Segmentum Ultima, the region of the galaxy now known as the Maelstrom Zone was first explored during the Great Crusade of the 31st Millennium. Second in size and extent only to the Eye of Terror, the Maelstrom is a vast Warp rift that scars both the physical universe and the fabric of the Immaterium beyond.The Maelstrom covers an area many hundreds of light years across, and its presence in space is marked by a vast, slowly turning gyre comprised of nebulae, dust and stellar material in which countless stars and worlds have long been lost to the Empyrean.During the Great Crusade, the vast armies of the Emperor of Mankind attempted to penetrate the Maelstrom and cleanse it of the evils that lurked within. The wealth of the worlds bordering the Maelstrom has drawn Mankind to the Maelstrom Zone time and again despite its manifold hazards and difficulties, and indeed there is ready evidence of Humanity's presence in the region as far back as the Age of Technology.The Maelstrom Zone has also drawn Humanity's enemies as well in their countless number and diverse loathsome forms. Hundreds of warships and thousands of troops were lost in the early campaigns during the Great Crusade era, and with the rest of the galaxy to reconquer, the Emperor declared the region Purgatus.In the years following the Horus Heresy, Primarch Roboute Guilliman of the Ultramarines Space Marine Legion decided that the inhabitants of the Maelstrom were too great a threat to the shaky stability of the recovering Imperium to ignore, and ordered the surrounding regions reinforced in an effort to contain any attacks that might originate from within.Over time, the Imperium slowly established several important Imperial outposts within the Maelstrom Zone during the 38th and 39th Millennia. These outposts rose to prominence as flickering beacons of Human influence and strength within the region. The three vital star systems that formed the links in a distant chain that allowed the resources of the Maelstrom Zone to flow into the coffers of the more established Imperial sectors beyond were the star systems of Cygnax, Sagan and Badab. As the situation in the Maelstrom became ever more volatile, this path of Imperial commerce came increasingly under threat.By the middle of the 41st Millennium, the heavily militarised Hive World of Cygnax located in the star system of the same name was the most populated planet in the northern Maelstrom Zone. Having long been a lynchpin of Imperial control of the region, Cygnax was a key strategic world, forming a bulwark against aggressors and serving as a safe port for Imperial merchant and naval vessels.In the year 557.M41 disaster struck, when, with the suddenness of an onrushing storm, Cygnax succumbed to corruption from within and attack from without. The planet rapidly fell into bloody civil war between its Imperial garrison and Death Cult nihilists, backed by the intervention of the dread Chaos Space Marine warband known as The Reborn. Despite the intervention of the Mantis Warriors Chapter, which itself had made a home in the nearby Endymion Cluster Sub-sector, the death toll rose exponentially into the millions.The Death Cultists managed to gain access to part of the Cygnaxian missile defence network, and in a suicidal rage unleashed a rain of atomic and plasma warheads upon the doomed world, shattering its hive cities and disrupting the planet's orbit for several standard years. The resulting permanent nuclear winter, radioactive fallout and tectonic upheavals annihilated all life on Cygnax.With the fall of this key world, Imperial control of the northern Maelstrom Zone swiftly crumbled. Without Cygnax, along with other Imperial losses suffered in the region over the previous few centuries, vital military supply chains stretching as far as Bakka and Terra itself were threatened, forcing the Adeptus Terra to act.