Located in the Ultima Segmentum, Donatos Primus is a Class Two Industrial World of the Imperium of Man. Heavily industrialised, the planet maintains close ties with the Adeptus Mechanicus and can be counted as a part of the Mechanicus' net of influence within the Imperium. As of 925.M41, Donatos' sizeable industrial output was reserved almost exclusively for the supply of the Mechanicus military forces defending the Forge World of Ryza, which was struggling to defeat two consecutive Ork WAAAGH!s.
Donatos Primus came under assault by the forces of Chaos during the Donatos War, a bloody campaign of reconquest launched by the Imperium to prevent its fall to the servants of the Ruinous Powers. Donatos was only saved through the sacrifices made by the Imperial Knights of the Knight World of Adrastapol.
Before the dramatic events of the Donatos War, the world of Donatos Primus had faced its fair share of workers' strikes and other petty revolts, but they had remained a purely internal matter. In fact, small-scale rebellions were so common on Donatos that the Adeptus Mechanicus had deemed it fit to secure its vital supply chain by granting the world a series of extensive fortifications, locally known as the Adamant Citadels.
Designed both to repel invaders from space and on the ground, it was ultimately the rebels' ability to knock out these fortifications that led Donatos Primus' latest rebellion to grow into what was called the Donatos Uprising, a global planetary revolt that also spread to parts of the Donatosian Planetary Defence Forces. With the Adamant Citadels still functional and in Imperial hands, even the scale of the revolt -- though sizeable -- did not disturb Lord Governor Gnossul, who hoped to quell the rebellion with the help of the Adeptus Arbites and its own Loyalist PDF regiments.
Unfortunately, the Adamant Citadels that had kept the Uprising from spreading to the southern part of Donatos' principal continent suddenly failed, deactivated by infection with a pernicious scrap-code (computer virus) of Dark Mechanicum-origin. Worse yet, Chaos Space Marines, their heraldry displaying the heretical icons of the of the Word Bearers Traitor Legion, were sighted leading the rebellion. Varakh'Lorr, a Dark Apostle of the Word Bearers and the leader of the warband known as the Scribed Blade, was the true architect of this rebellion.
Led by their dark masters and with the Adamant Citadels now in their hands, the rebels represented a real threat to the rule of Lord Governor Gnossul and his forces. The heroic sacrifice of the 19th Regiment of Donatos' Planetary Defence Militia -- which had sacrificed itself to ensure that the southern Adamant Citadels were bereft of power -- bought the Imperial forces enough time to retreat and dig in. Although the Donatos Uprising would seize much ground and even kill Donatos' Planetary Governor, the Imperials had time to send an astropathic distress signal to the sector authorities. Since the industrial and petro-chemical complexes of Donatos were far too valuable to the economy of that region of the Imperium to leave in enemy hands or simply destroy from orbit, a reconquest of Donatos Primus was ordered by the sector high command. This assault became known as the Donatos War.
With the support of several regiments of the Astra Militarum, the Imperial Knights of the nearby Knight World of Adrastapol were ordered to undertake the reconquest of Donatos Primus. Command of the operation was given to the seasoned veteran and ruler of that world, High King Tolwyn of House Draconis. Adrastapol would contribute over 300 Imperial Knights to the campaign. Facing such potent adversaries, the Donatosian rebels lost several important battles which saw them forced to retreat north of Donatos' equator and back to the near-impregnable fortifications of the Valle Electrum, the beating heart of the Adamant Citadel network.
High King Tolwyn realised that regaining control or destroying the Adamant Citadels would bring victory to the Imperium and concentrated all his efforts upon the conquest of the Valle Electrum. Alas, as the High King led the combined Imperial forces in their first assault, he was betrayed by two of his closest allies, Archduke Duncan of House Wyvorn and Viscount Gerraint of House Chimaeros, who switched sides in the middle of the battle. With nearly half of his Knights turning upon him, caught between these Traitors and the fortifications of the Donatosian rebels, the Imperial forces suffered heavily, including the loss of their own commander. However, Tolwyn's sacrifice allowed a force of his own Knights to escape. Led by Tolwyn's son and heir, Danial Tan Draconis, these survivors went to ground and proved to be a thorn in the enemy's side.
Suffering several drawbacks, including another ambush which heavily reduced their numbers, the Loyalist Knights of Houses Draconis, Minotos and Pegasson were able to maintain their cohesion as a fighting unit and survive in numbers large enough that they still posed a threat to the enemy's plans. However, the forces of Chaos present on Donatos Primus were not united in their ultimate aims. Varakh'Lorr intended to sacrifice Donatos' population as part of a great Chaos ritual intended to fuel his ascension to Daemon Prince, whilst the Traitor Viscount Gerraint Tan Chimaeros, the self-proclaimed High King of Adrastapol, sought to take control of Donatos' resources and armies to ensure Adrastapol's secession from the Imperium of Man.
As the Traitor factions turned on each other, disabling the vital Adamant Citadels in the process, the Loyalist Imperial Knights mounted a near-suicidal second assault upon the Valle Electrum. Danial Tan Draconis' plan proved an unmitigated success, killing both the leaders of the Renegade Knight Houses and Varakh'Lorr while simultaneously allowing for the destruction of the Valle Electrum. High King Tolwyn's original analysis proved true, as without control of the Adamant Citadels, the Traitors were soon vanquished. Remnants of the Word Bearers' Scribed Blade warband and the Renegade House Chimaeros escaped destruction and were mercilessly hunted by the Freeblade Knight known as the Knight of Ashes, the last loyal son of House Chimaeros.
Like Old Earth, Donatos Primus features water in abundance, vast oceans that have not yet succumbed to the heavy levels of pollution that result from the waste output of Donatos' many heavy industries. In contrast to Terra, the landmasses of Donatos Primus are relatively few and number only two continents. The smaller one, Continent Secundus, is sparsely inhabited and is mainly used as a toxic waste disposal centre for the by-products of Continent Primus' manufactoria. Both continents are separated by the wide expanses of the Raekesh Ocean.
In stark contrast to its counterpart, Continent Primus is a heavily urbanised super-continent. The northern shores of Continent Primus are so densely populated that several hive cities have expanded into each other to form what is commonly referred to as the "Northern Industrialia." As one travels south, the hive cities become smaller until they are no longer true hives. The southern and northern settlements of Continent Primus are connected by great macro-highways that are six lanes wide on each side. Most of the world's ports are concentrated to the south, on the Pentakhost Peninsula.
Donatos Primus' central landmasses are quite mountainous, though even the mountain peaks have been claimed by the expansion of Donatos' hives and given over to hab-blocks or the military fortifications of the Adamant Citadels.
- Adamant Citadels - The Adamant Citadels are a series of heavy fortifications erected by the Adeptus Mechanicus to protect their interests on Donatos Primus. The Citadels vary both in size and in aspect. The mightiest of them, Ironpeak -- which forms part of the defences of the Valle Electrum -- is located within Donatos' highest mountain. All Adamant Citadels carry an impressive arsenal of void-capable weaponry, including missile silos or towering Macrocannons, but their design also allows them to fire those immensely powerful weapons and ground targets. This was a requirement of the Mechanicus, for the Adamant Citadels' primary goal is to occupy the terrain and prevent riots or rebellions from spreading to other manufacturing sites that could imperil the planet's industrial output.
- Angellum Stellar (spaceport) - The Angellum Stellar spaceport is only one of several installations of this type on Donatos Primus, but this particular spaceport derives its strategic importance from its proximity to the Valle Electrum. It was at Angellum Stellar that the Traitor Archduke Tan Wyvorn would have his House's secret weapon, a relic Acastus Knight Porphyrion, delivered to him.
- Pentakhost Peninsula - Located to the south of Continent Primus, the Pentakhost Penisula is a promontory formed by a great gulf of the Raekesh Ocean. Less heavily urbanised than the northern Industrialia, the Pentakhost Peninsula was selected by Imperial forces as their principal landing zone during the Donatos War for two principal reasons. First, its distinctive bottleneck link to the mainland meant that the Peninsula could be easily defended. The Knight Houses of Adrastapol had even employed some of their Drop Keeps along its narrow northern tip as a fortification line whilst landing their troops. Second, as an industrial grade seaside-terminal with good connections to Donatos' road network, the Pentakhost Peninsula possessed the necessary infrastructure to handle the expeditionary force's logistic needs.
- Square of Martyrs - The Square of Martyrs is a great ceremonial plaza at the heart of the Valle Electrum which, before the Donatos Uprsing, was bordered by towering statues of Imperial Saints and heroes, all of which were subsequently destroyed by the insurgents. During its occupation by the rebel forces, it was on the Square of Martyrs that the Dark Apostle Varakh'Lorr preached to the "liberated" masses of Donatos' workers. During the Donatos War, the plaza became a battlefield where the Imperial Knights of High King Danial Tan Draconis defeated their Renegade brethren. Both Viscount Tan Chimaeros and Archduke Tan Wyvorn were slain in the Square of Martyrs.
- Valle Electrum - The Valle Electrum was one of two principal sites tasked with supplying Donatos Primus' Adamant Citadels with energy. With its twin, the Peninsulum Manufactorii, destroyed early in the war, the Valle Electrum became the keystone to the Adamant Citadels and thus to Donatos Primus itself. Though its detractors often reduced its importance to that of a glorified Plasma Generator, the Valle Electrum was much more. It was Donatos' most heavily defended and secure location. Not unlike the Imperial Palace on distant Terra, the Valle Electrum was a fortified mountain range, a world within a world, fully self-sufficient and heavily defended. To the north, the mightiest of the Adamant Citadels, Ironpeak, watched over the heartland of the Valle Electrum. All traffic that wished to reach it had to first pass through one of the three mountain passes -- the Pass Primus, the Maw Omnissan and the Nortus Maximal. Each pass was well-defended by bunkers, fortifications and pill-boxes. The hab-towers themselves were double-reinforced and were armed with automated Icarus Autocannon air-defence batteries. Once inside the Valle Electrum proper, sprawling forges and manufactoria covered the ground leading to the Square of Martyrs which separated the towering buildings of Generatorium One and Two. It was there that the heaviest fighting of the Donatos War occurred. With Danial Tan Draconis' victory over the Heretics and Renegades, the Valle Electrum was destroyed by the Imperial Navy's orbital bombardment.
- Kingsblade (Novel) by Andy Clark