The 'Yren Irtan

First contact
The Yren ‘Irtan, or “Bugs” as they are known to most Human Alliance soldiers, are unique in not having originated from this galaxy. They were first discovered by the Nuitan of Argosy Sinaer, which was wandering the southern fringes of the galaxy (although the galaxy does not have north, south, east, or west, Human Alliance cartographers tend to assign it easily recognisable values to make it easier to understand). The Argosy’s seers sensed an unnatural disturbance in the Ether, which they were unable to probe, although they did discover that to remain in position would be suicidal. Leaving behind armoured probes, they withdrew to the nearest systems, to warn the inhabitants of the approaching danger. The probes discovered something not seen before in the whole galaxy. The approaching fleet appeared to be a collection of unbelievably massive creatures, capable of propelling themselves in space, and containing many smaller creatures. Some of these beasts detached themselves from the larger ones and destroyed the probes, but not before the Nuitan had discovered enough to guess that these creatures were not exactly friendly. Pausing briefly to warn the humans, Sinaer departed rapidly from the area – some of the more ancient of the Nuitan grieving, for the fleet had come from the same direction as one of the galaxies to which one of their colony ships had departed. The Human Alliance, never trusting of an alien, did nothing. Until the fleet hit the outermost system on the southern fringe. The creatures, dubbed the Yren ‘Irtan or “Eaters of Stars” by the Nuitan, completely stripped the planets bare, consuming everything biological and leaving only a ball of rock. The Alliance only learnt of this when a fleeing escort-class ship reached the next system, after which armies were immediately mobilised for deployment in the next nearest system, and the sector fleets placed on standby. Fortunately, the Yren ‘Irtan did not possess faster-than-light travel technology, so the Human Alliance had plenty of time to assemble its forces. The battle took place in the Kirval system, and that is where the official human name for the Yren ‘Irtan comes from – the Kirvests. Fortunately, Kirval is the home to a space marine chapter, who were quite happy to lend their might against the alien menace.

The Battle of Kirval
The battle began with a massive fleet engagement on the outside of the system. The Alliance fleet was not able to stand against the invader, mainly because human ships were designed to fight enemies who had the manners to stay at range, not close and try to eat the other side’s ships! However, significant losses were inflicted upon the invader before Admiral Donelt signalled the general withdrawal. The fleet retired to Kirval I’s orbital dockyards, abandoning the rest of the system to its fate. On Kirval IV, the largest and outermost planet in the system, the defenders were preparing. Kirval IV’s population lived mainly in a belt of cities in the equatorial jungles, while the rest of the planet was fertile grassland using for agriculture. The Alliance commanders decided to abandon the farmland and concentrate their efforts on defending the population centres, so entrenched heavily at the outskirts of the jungle and then around the cities themselves. 30 regiments of planetary defence force were deployed, along with nearly 150 regiments of off-world Alliance Guard, and the entirety of the Flaming Skulls Space Marine Chapter. The enemy fleet was now reasonably small, and the commanders were confident that they could hold. Two weeks after the fleet engagement, the Yren ‘Irtan arrived in orbit around Kirval IV. Unlike the usual planetary assaults – deploying troops by drop ship and establishing a beachhead – the Kirvests simply dropped their creatures onto the planet, bound together in tight bundles and protected by a thick layer of heat-resistant membrane, that decayed on contact with oxygen above a certain level. Very rapidly, huge numbers of the enemy had landed, despite the best efforts of the defence cannons. The Kirvest foot troops also presented a new form of opposition to the Human Alliance. The Kirvests are a completely organic race, and have no material technology. Every weapon or piece of equipment they own will be an animal in itself, typically mind-fused to the larger creature that holds it. Moreover, the creatures themselves, even the most developed, seem entirely subject to some controlling authority, which the largest and most powerful creatures seem to act as a beacon for. This intelligence has been dubbed the “Collective” by Alliance researchers, and the Autil ‘Yren ‘Irtan by the Nuitan (demonstrating the clunky language system of an otherwise very graceful race). The defenders quickly learnt that the Kirvests were not like ordinary opponents. They did not run away, even under horrendous losses, unless the Collective’s link was cut. This was quickly learnt, and defenders began to target the larger creatures. However, each new discovery had an immense blood price attached – twelve regiments were wiped out before command even formed a proper picture of what they were up against, and the Yren ‘Irtan were up to the city walls. The new tactics were beginning to take their toll, but the fleet above seemed to have an infinite supply of creatures to hurl at the defenders. It was at this point, as the first city fell, that Sinaer decided to enter the stage. The Nuitan seers had surmised that to allow the Yren ‘Irtan a foothold would be fatally dangerous to their race as a whole, and the Human Alliance would benefit from what they had learnt on Kirval IV. Now, while the Yren ‘Irtan’s ships were more than a match for the Alliance ships, whose massed batteries of smaller weapons had made little effect on the armoured carapaces of their foes, Argosy Sinaer carried weapons designed for blasting small planetoids out of its way, and its mechanics had been busy modifying the Argosy’s fleet to better deal with the invader. Despite all this, the Nuitan still took immense losses, and from this day forward Sinaer has been a shadow of its former glory, but their prompt actions succeeded in destroying the Yren ‘Irtan fleet. Without reinforcements to be had, the creatures left on Kirval IV quickly melted away into the jungle. The defenders, weary but victorious, pushed on after them and found their planet changed beyond recognition – alien flora and fauna sprouting in what had once been lush grasslands, with hissing pools of acid which looked suspiciously like open-air stomachs… With no other option, the Alliance commanders withdrew from Kirval IV, and the planet was fusion-bombed into an empty wasteland by the Inquisition. The entirety of the Kirval system was evacuated, and the whole area declared quarantined.

Subsequent incursions
Since Kirval, there have been many more incursions by the Yren ‘Irtan, each more deadly than the last. While the Human Alliance learns fast, the Collective seems to be able to adapt just as quickly, evolving its creatures to avoid whatever threat presents itself. The incursions are also becoming progressively greater in size, and more and more of the southern fringe of the galaxy is being overwhelmed by these voracious aliens.