The Nimbosa Crusade was an Imperial Crusade undertaken in 993.M41 by the Black Templars, Imperial Fists, Raven Guard, and Ultramarines Space Marine Chapters against the T'au Empire following the T'au conquest of the Civilised World of Nimbosa. All of these Chapters have reputedly fought the T'au on the heavily contested planet at one time or another and the world has changed hands many times.
When Hive Fleet Kraken began to threaten worlds on the Eastern Fringe of the Imperium of Man in 992.M41, the High Lords of Terra responded by stripping the worlds on the border with the T'au Empire of Imperial forces. The T'au Empire was quick to recognise this redeployment and soon moved to take advantage, beginning the period of T'au history known as the Third Sphere Expansion. The T'au had soon annexed a whole swathe of Imperial worlds along the border. Nimbosa was one of the most important of these worlds, and the Black Templars would be instrumental in retaking it for Mankind.
The T'au forces under the command of O'var (Commander Brightsword), began the invasion of Nimbosa with a landing by T'au Fire Warriors in overwhelming numbers. The T'au had soon established control over most of the world.
First Phase: The Defence
The only Imperial force left able to resist after the first phase of the Third Sphere Expansion was the 9th Vostroyan Firstborn Regiment of the Astra Militarum under the command of Graf Toschenko. Toschenko moved quickly to fortify the Nimbosan factory city of Polia. Brightsword's first thrust used Kroot warriors to identify Imperial Guard strongpoints to be bombarded by T'au armour. The T'au's Kroot auxiliaries suffered heavily in the initial push but the strategy was successful and the T'au eventually gained a foothold in the city and with relentless attacks the T'au foothold began to grow. Graf Toschenko authorised a desperate counter-attack to maintain the Imperial lines; he had come to realise that the T'au policy of isolating and reducing each Imperial stronghold would soon break his hold on the city. The main counter-assault fell in and around the central Cathedral.
At first the Imperial counterattack proved to be a complete success. Kroot auxiliaries were caught by surprise and fled from the attack, falling back towards the T'au's armoured units. Graf Toschenko committed his last reserve of men and his few remaining tanks to exploit the gap made around the Imperial Cathedral of Polia, however, the discipline of the isolated T'au forces held, and the Imperial salient turned into a trap. The Imperial vanguard and reserve were decimated by ambush and bombardment directed by T'au Stealth Suit teams spotting for artillery and guided munitions fired from the T'au rear areas.
At the vanguard of the advance, Graf Toschenko's command squad was caught out in the open and destroyed by hidden T'au Fire Warriors. The Graf personally took up the regimental standard and desperately called to his men to rally. Imperial resistance hardened around the Graf and the fight degenerated into bloody close street fighting. But by now Imperial resistance was all but broken and with the death of the Graf combat finally ceased and Nimbosa was firmly in the hands of the T'au Empire. But their grip would not last long, for the Imperium called for a Crusade to free Nimbosa and the other Imperial worlds that had been lost to the upstart T'au.
Second Phase: The Crusade
The initial battles of the Crusade with the T'au took place in space; aboard the orbital space stations the aliens had placed in geo-stationary orbit around Nimbosa. The Black Templars' Strike Cruiser Dorn's Wrath used its speed to evade the incoming fire and closed to attack range. Using boarding torpedoes and Thunderhawk gunships it penetrated the hull of the target, designated Orbital Primus, and allowed the household guard of Castellan Folkert to be the first to fight the enemy.
The T'au Fire Warriors stationed aboard Orbital Primus turned the corridors of the space station into killing grounds and a warren of deadly ambushes. The Black Templar force countered this by splitting up into small squads and attacked the defenders from multiple directions, using grenades and Chainswords to smash their way through the bulkheads. This enabled them to outflank the defending T'au forces, who were ineffective at close combat, and crush the aliens' resistance.
After fighting their way through to the gunnery controls of the orbital, the Space Marines were able to turn the guns of the station on the other T'au orbitals. This, combined with the assaults of the Imperial Navy, was too much for the remaining orbitals to withstand.
Finally Castellan Folkert destroyed the geo-stationary gravitic emitter anchors of Orbital Primus and let it fall through the atmosphere of the planet, destroying the space station in a rain of fire. Meanwhile, the Ultramarines' 1st Company smashed into the defending T'au garrison, eliminating the T'au's anti-air turrets and making short work of the T'au leaders. With the T'au's command-and-control eliminated, the Astartes forces were able to make nearly unopposed planetary landings and easily root out the remaining T'au ground forces on Nimbosa.
The campaign ended with the successful recapture of Nimbosa by the Imperium and the destruction of the entire T'au garrison.
There is an inconsistency in the dating of the Nimbosa Crusade in published sources. Codex: Imperial Guard (5th Edition) makes clear that the Nimbosa Crusade occurred in 790.M41. But Cities of Death holds that the T'au assault of Nimbosa was only made possible because of the encroachment of Hive Fleet Kraken on the Eastern Fringes of the galaxy, a Hive Fleet which did not appear until circa 992.M41. Even further confusion is added by the fact that the Codex: Tau Empire (4th Edition) claims that the Imperial counterattack came within only 4 months of the loss of the world and the short story Assault on Nimbosa actually places the Crusade in an ambiguous time period some time after 999.M41.
- Codex: Imperial Guard (5th Edition), pg. 22
- Codex: Tau Empire (4th Edition) pp. 14-15
- Cities of Death, pp. 56-57
- White Dwarf 314 (UK), "Marshals of the Great Crusade - Folker," pg. 96
- White Dwarf 312 (UK), "Righteous Victories," by Graham McNeill, pg. 19
- Assault on Nimbosa (Games Workshop Online Short Story)