Hive Fleet Gorgon

Hive Fleet Gorgon was a Tyranid Hive Fleet that threatened the Eastern Fringe of the galaxy, and in particular, the borders of the Tau Empire. It's one of the first splinter fleets created after the First Tyranic War ended with the imperial victory in the Battle of Macragge in 745.M41.

Aftermath of Macragge

The destruction of Hive Fleet Behemoth during the Battle of Macragge was the first major victory against a major Hive Fleet. The splintering of the remaining nid Hive Ships and its dispersal throughout the area kept imperial forces very busy, but even with all that activity, there were too many isolated splinters, certainly too many for the imperial forces to find and purge alone. Thus, slowly but steadily, some smaller splinter fleets began growing in mass and power, feeding on backwater planets. After a while, it started to move further and further from the Imperium's borders, finally making contact with the Tau Empire.

Tau's first contact with the tyranids

By the time Gorgon arrived to the first Tau controlled planets, it had grown to become quite a threat in its own right, although it didn't reach the size of the original Behemoth by a lot. The Tau knew something was very wrong in the area, due to the loss of multiple trading posts in Imperium-controlled territory. In 900.M41, Gorgon attacked the planet of Sha'draig, which would become the battlegrounds for the first Tyranid-Tau war. The Tau's forces were able to trench themselves withing their ships and bases, and just let their drones make good work on the hordes of tyranids. After a distress signal was launched, a rescue fleet was sent to the colony as soon as possible, arriving soon enough to assist the planet, but long after the moon was lost. The landwar didn't go well for the Tau either. Despite the effords of the kroot forces dispatching tyranids quite efficiently in the forests, the nid's advance kept going and the loss of the planet became quite clear for Tau command. In a last ditch efford to keep the planet, and going against orders from their superiors, the Fire Cast commander launched a series of suicide attacks in order to kill the bigger synapse creatures and cause major havoc upon the invaders. Against all odds, they managed to succeed, and with a last final push, managed to kick Gorgon out of the planet. A quite impressive feat considering the Imperium took many planets lost before managing to obtain a major victory against the nids. Score one for the Greater Good, I guess. Then again, the Tau didn't destroy Hive Fleet Gorgon here, it just moved on to other planets, and Sha'draig ended up so damaged by the invasion that it was abandoned shortly after.

The war against Gorgon: adapt or die

After this first encounter with the tyranid fleet, the Tau authorities were scared shitless. Hive Fleet Gorgon was a threat unlike nothing they had seen before: the planet was in ruins. Poisoned and bereft of resources, it barely had any use now for anyone. Most of the forces that fought the Hive Fleet had been wiped out, and most of Gorgon was still out there, attacking nearby Tau outposts, not that much worse for wear. Unlike the Imperium, there was no chance of negotiation, and unlike orks, once a planet is lost it can never be recovered (bad for a massive empire like the Imperium, almost unbearable for the small Tau Empire). To top it all off, Hive Fleet Gorgon was exceptionally apt in changing and adapting its strategy in the face of new threats. The Tau forces, way more flexible than its Imperium counterpart, had fought the nids on Sha'draig with many strategies: massive drone attacks, stealth attacks, kroot charges and traps, stealth suits, kamikaze attacks... And to all of them, the nids had developed a strategy to deal with each one. One of the most important adaptations of the Hive Fleet was the developement of carapace body armour strong enough to deal with plasma and ion weaponry, both favourites of the Tau military, and creating faster and faster creatures to meet the bluies in melee combat, which Tau are too weak against. The Tau kept changing their strategy too, either spamming droids to deal and kroot armies to deal with the swarms, stealth suits to catch the bigger organisms off guards, switching their weapons to older models based on outdated tech once the nids adapted to plasma and ionic tech... The Tau managed to get an edge in their fights thanks to the biological nature of the tyranid weaponry and adaptations. Changing the DNA of your units and then spawning them fast enough into the battlefield took longer than just using normal tech, which limited the size and strength of their units during vital moments, which was then used by the Tau to snipe the bigger synapse creatures from affar and break the cohesion of the tyranid swarms.

The Necrons and the Imperium join the fray

After Gorgon's retreat from Sha'draig, the Hive Fleet started looking for other planets to eat, to replenish the losses suffered on Sha'draig. One of the more interesting scenarios was the Ka'mais system. A rather undefended planet, the local forces were no match for the relatively small fleet coming for them. When all hope seemed lost, a dormant necron tomb awaken on the dead moon of the planet, managing to fight off the tyranids in space. This became the Tau's first contact with the necrons, which ended up with all of the bluies killed and harvested by the necron forces, after the local ethereal made the totally sound decision of declaring a pary in their honour. The few survivors of the planet (plus the ones from nearby worlds too, having heard of the utter slaughter the necrons had unleashed there) were evacuated and fled, only for Hive Fleet Gorgon to eat them once in space.

The war was not going well for the Tau in other fronts either. They had lost quite a lot of ships due to the new and improved bio-ships, now immune to Tau weaponry, and a couple of small worlds had fallen to the Hive Fleet already. Suddenly, and without warning, a huge fleet from the Imperium of Man emerged from the Warp. The fleet was originally meant to fight in the Damocles Crusade, but it had become stuck in the Warp for more than a century. Not knowing the Crusade was lost, they immediately attacked the nearest attack planet. Trying to make sense of the situation, the Tau authorities tried to bring them up to speed with the latest events. At first, the fleet admiral didn't believe the obvious lies of those filthy xenos, but then they found Hive Fleet Gorgon, and decided it was a bigger risk than the bluies. Displaying an uncaracteristically level of teamwork, Imperial and Tau forces were able to fight Hive Fleet Gorgon to a standstill, cutting deep into their forces and severely hurt most of the bio-ships. Considerably wounded, Hive Fleet Gorgon tried to ran away from this sudden oposition, but it was chased down and destroyed by the combined forces, its rapid adaptation ability rendered useless when fighting two combat docrines as different as the Tau and the Imperial Guard.

Aftermath of Gorgon

By 903.M41, Hive Fleet Gorgon had practically been erased from existence. Most of its reproductive organisms had been destroyed, and the ones left were too small to efficiently take over a planet, and thus starved to death. The Tau Empire had learnt a valuable lesson fighting the forces of the Great Devourer, a threat it would soon became commonplace in its borders. They had also made first contact with the necrons, although that threat would prove much different from the tyranid menace. The Tau-Imperium alliance quickly ended once Gorgon had been slain, but considering it lasted long enough to wipe out the Hive Fleet until it was no longer a threat, it can be considered a massive success for imperial and Tau diplomacy.

Tyranid Hive Fleets
Major Hive Fleets:	Hive Fleet Behemoth - Hive Fleet Kraken - Hive Fleet Leviathan
Minor Hive Fleets:	Hive Fleet Colossus - Hive Fleet Dagon - Hive Fleet Gorgon - Hive Fleet Hydra - Hive Fleet Jormungandr Hive Fleet Kronos - Hive Fleet Moloch - Hive Fleet Naga - Hive Fleet Ouroboris - Hive Fleet Tiamet