Baroda was an Imperial Knight World located in the Grail Abyss at the extreme border of the Segmentum Obscurus and the Imperium itself. Before the Age of Strife Baroda was a populous world, rich in minerals and home to dozens of Knight Houses which would dramatically decay and go on to destroy themselves in internecine warfare.
Baroda is perhaps best known for being the former homeworld of the infamous and ill-reputed House Makabius, which committed countless atrocities alongside the Traitor Death Guard Legion throughout the Cyclops Cluster. The planet was abandoned early on in the Horus Heresy, forcibly evacuated and stripped of its resources and manpower by the orders of the sinister Death Guard Primarch Mortarion in 007.M31.
One of the many Knight Worlds seeded towards the end of the Dark Age of Technology, Baroda was a terrestrial type world with a variegated climate possessed by the typical saurid megafauna associated with such worlds. Isolated within the grip of the Grail Abyss, Baroda was spared from outside influence and alien assault during the Age of Strife, but suffered from a propensity to terrible climatic storms.
Having been colonised during the Age of Technology, most of Baroda's easily accessible mineral resources had been exploited in millennia past, resulting in a ever-increasing lack of resources which led in turn to frequent clashes between its Knight Houses for power and control.
This lack of resources ultimately kindled a full-scale war between the Knight Houses for the possessions of the last bore mines and storm-proof fortress refineries, many Knights being now powered by reverse-engineered petro-chem engines. This civil war would last for Terran centuries, ending only in 831.M30, with the fall of the last stronghold of House Wentorth, leaving House Makabius as the sole ruler over Baroda's storm-tossed oceans.
By the time Baroda was reclaimed by the Imperium, even the surviving Makabius Knights had been reduced to fossil fuel-burning, ill-repaired hybrids of what had come before. While re-joining the Imperium and contact with the Mechanicum rejuvenated Baroda's technology and gave it a place in something far greater, its isolation in the Grail Abyss still served to keep it far from regular contact and influence.
This integration wasn't however obtained peacefully, as the warlike and proud House Makabius refused to simply submit to these strangers from another world. Battle was joined at Arbren Moor, where the Astartes of the Imperial Fists Legion swiftly defeated the pride of House Makabius' Knights in a ritual battle. Lauded for their tenacity by the victors, but ultimately denied an important role at the forefront of the Great Crusade due to its neglected state, House Makabius was left with no other choice than to stay behind on their homeworld and slowly rebuild.
In the years that followed, the flower of Baroda's noble youth fled the world, its young Knights joining the forces of the Great Crusade as Questoris, never to return; many turned Freeblade if they were forbidden by their embittered lords in a vain attempt to stall the exodus. Tensions mounted between House Makabius and the recently rediscovered House Vyronii, which they saw as rivals for the patronage of the Forge World of Mezoa to whom both Houses looked for supplies and equipment.
Open war was purely avoided by the Makabius' lack of interstellar transportation and functional Knight armours. It would be then that one of the exiled Knights of the Makabius, Markan Hrotham, would distinguish himself, drawing the Warmaster Horus' gaze upon him and his house. Already turned Traitor, it would prove simplicity itself for Horus and his agents to prey upon the collective resentment of House Makabius and make them renounce their oaths of fealty to the Emperor.
With the Warmaster's new favours, Baroda and House Makabius entered a short period of prosperity. As would later be realised by the Imperial Historicae Department, the military build-up of House Makabius would be part of the opening moves of Horus' rebellion and was achieved shortly before the Istvaan III Atrocity. Having denounced its ties with Mezoa, new Knight armours and weapons flowed from the Warmaster's Dark Mechanicum allies to Baroda, and House Makabius quickly grew stronger.
As the Imperium tore itself apart in the catastrophic events of the Heresy, House Makabius naturally sided with their new patron and benefactor, the Traitor Warmaster Horus Lupercal. In the closing days of 006.M31 the war reached the Coronid Deeps. By then Baroda was already on a war-footing, eager to cover itself in glory in this new war that now erupted across the Imperium.
This did not lessen the shock when instead of the Warmaster's personal patronage, Mortarion, the Reaper of the Death Guard, came bearing the personal seal of the Warmaster, and claimed House Makabius' oaths of servitude and had them join his dread fleet. Under the order of the Warmaster, Baroda was stripped of everything useful it had to offer: mineral resources, fossil fuel, machinery, manpower and the military might of House Makabius and its retainer forces. Departing rapidly thereafter, the newly combined fleet headed to the Cyclops Cluster to begin a path of massacre, genocides and atrocities that would take it all the way to sacred Terra in the final battle of the Heresy.
- The Horus Heresy - Book Four: Conquest (Forge World Series) by Alan Bligh, pp. 70-71, 106-113