he world of Tallarn was once a fertile planet bathed in the gentle orange light of its twin suns. Oceans, plains and lush jungles covered its surface, and its people prospered.

All of this ended during the Horus Heresy.

CHAOS ATTACK!

n a devastating surprise attack, the Iron Warriors Chaos Space Marines struck the planet. Thousands of virus bombs rained down on Tallarn and the people ran to the enviro-shelters deep beneath the surface. As they hid, safe from the devastating bio-infestation, the deadly coils of DNA mutated as they were programmed to do. Animals, plants, even insects died as the virus did its work, destroying the planet's eco-system and leaving an empty shell.

After seven weeks of isolation the virus had run its course and the remaining people of Tallarn emerged upon the surface. They found a world covered with the acrid slime of plants and corpses not yet decayed – for the world was completely sterile, without even bacteria to aid the decomposition of its dead.

The Iron Warriors sent their task-force to repossess the world for the Dark Gods of Chaos. From underground bunkers the Tallarn forces emerged to do battle with the invaders. Soon, reinforcements from both sides arrived, rival space fleets bringing vast armies to fight over the worthless remnants of the dead planet.

The Battle of Tallarn raged for many months and was the largest armoured conflict of the Horus Heresy. Outbreaks of viral infection from rogue DNA residue made it almost impossible for infantry to operate outside their protective shelters. The battle was finally decided by armies of tanks. When the fighting ended the empty, putrid wastes of Tallarn were littered with the wreckage of more than a million shattered vehicles.

A Hollow Victory

Chaos was driven from Tallarn at great cost, yet for all the millions that died there seemed little gained from the fight. The planet was destroyed and rendered useless for large scale habitation, industry or agriculture. The armies of the Imperium might well have given up Tallarn had their commanders realised the extent of the devastation, but once the armies were in motion there was no going back.

At the time the Chaos attack made little sense. It seemed insane that even the fickle Gods of Chaos should expend such energy fighting over a devastated world of no particular strategic significance. But in the aftermath of the Horus Heresy there were few left to ponder such questions. Amongst the evils of the time it was just another demonstration of the random destruction of Chaos.

Tallarn Survives

Within a thousand years of the Horus Heresy Tallarn evolved into a very different world from the prosperous planet of former times. Deserts of sulphurous sand stretched from pole to pole and all water disappeared except for a thin residue in the atmosphere. No vegetation remained on the surface exposed to the blistering, wind-blown sands. All that grew was the carefully husbanded crops of the Tallarn themselves, sheltered in their protective horticultural domes.

The surviving Tallarn now lived in domed towns or in natural caverns hollowed out in the planet's rock. Fierce winds drove the Tallarn into their shelters, corrosive sulphur storms made all travel risky, and eventually a system of tunnels was built to facilitate travel beneath the surface.

Above their settlements the Tallarn built vapour traps to catch water from the thin atmosphere. These tall towers still stand above their domes to this day, and all the water they use is caught by these cunning devices and channelled into subterranean holding tanks.

A Secret Uncovered

During the construction of an arterial tunnel, Tallarn miners struck an outcrop of hard black rock. They were unable to break through this strange substance which was quite unlike any other they had encountered. After some days they decided to divert their tunnel to go around it. As they did so they discovered something very strange. At first the black wall seemed like a natural formation, but soon they realised they had uncovered a deliberate construction.

The initial excavations revealed a huge wall of strange black rock carved over its entire surface with weird entwined figures. The figures were human sized yet not entirely human, possessing a grace and beauty which rendered their grotesquely inscribed cavorting all the more perverse. Giant earth movers were brought in to dig out the layer of sulphur sand in which the wall was buried, and bit by bit it was slowly and painstakingly exposed to the daylight.

The Tallarn soon discovered the wall was not straight but curved, in fact part of a huge circle. Carefully their most skilled technicians worked to uncover the entire thing, a huge ring-shaped mound almost half a mile across.

Next: The Danger Awakes