Aside from the poisonous air, the green haze's obstruction of their vision was just as troublesome. Optical visibility was less than thirty metres, and even the Astartes' superhuman eyesight could see no farther than ordinary mortals.
The Chaos energy saturating the air interfered with the auspexes' normal operation.
Communications with the fleet in space suffered severe interference.
Everyone searched blindly for traces of Chaos, as though playing hide-and-seek across an open field.
Fortunately, Abaddon had deployed an enormous force, and the Loyalists soon discovered a vast area marked by landings and takeoffs.
Besides the numerous traces left by landing craft and transports, they also found large numbers of track and tyre marks on the ground.
Clearly, the Chaos Fleet had deployed considerable heavy equipment along with its troops.
Yet this planet seemed to have no entry in Imperial records.
The Chaos Traitors, however, appeared to be preparing to besiege a city.
Once they found a break in the interference and uploaded their intelligence to the fleet, the ships' Data Priests immediately processed it, quickly producing an estimate of the enemy's strength.
At least several hundred thousand Mortal Rebels had landed here, bringing substantial quantities of heavy weaponry.
Among the confused tracks on the ground, someone also found enormous footprints that could only have been left by Astartes power armour.
Clearly, Chaos was plotting something here.
A Dark Angels Strike Cruiser broke away from the fleet and gradually approached planetary orbit. It would provide fire support for the ground reconnaissance teams. Once they located the Chaos Traitors' forces, the Emperor's wrath would await them.
But as the reconnaissance forces followed the trail, the situation grew more complicated.
The vast Chaos force had raced dozens of kilometres across the surface before finally entering an enormous complex of ruined buildings.
Analysis of the