His own head span, his senses whirling with sickening dizziness, and his eyes began to water. But there was something else, something more than just the appalling, stomach-turning stench that was making him feel like this. It was an aura of intense, corrupting evil that accompanied the nausea-inducing miasma. Sergeant Vessig had never felt anything like it, but he knew it could only be one thing. This was what the touch of Chaos felt like. This was how it felt, how it smelt, how it tasted even, and every fibre of his body was repulsed by it.

Practically paralysed by the creeping miasma of rottenness, Vessig looked up into the cold visored eyes of the monstrosities emerging from the sucking mist.

The shifting murk revealed three grotesque figures clad in rusted, filth-streaked power armour of archaic design. Three more, still wreathed in the cloying filmy mist, came behind them.

Sergeant Vessig had only encountered the brothers of the Adeptus Astartes on two occasions in his long and varied career, the first time the White Consuls on the ice moon of Endathu and the second occasion during the Valerian Purges. Then he had seen warriors of the Howling Griffons Chapter in action, and impressive they had been too.

These abominations might once have been brethren to those other Space Marines, Vessig supposed. Now they were nothing but an affront to the God-Emperor and everything the great Imperium of Mankind stood for. These were the sons of Mortarion, the daemon-primarch of disease. The Death Guard.

The first abomination's armour was ruptured and cracked. Pipes dripping stinking bile protruded from these rents only to feed back into the bloated stomach armour of the Death Guard elsewhere. Three more pipes, not unlike those of a rebreather gas hood, connected the Marine's faceplate to a sphincter-like hole in the front of the distended chest plate. The auto reactive shoulder plates of the ancient armour bore the blasphemous iconography of the Plague Lord.

At first Vessig thought that the second Plague Marine had a spike on the crown of its helmet. Then seeing the corroded, ruptured ceramite at the base of the bony, grooved spike, the sergeant realised that it was in fact a horn protruding from the warped Marine's skull and subsequently through the top of its helm. As it took another step forward he saw that the toecaps of the traitor's ceramite boots had split, making it appear as though its feet were cloven hooves.

But it was the third of the repulsive figures that was the most revolting of all. The traitor was helmetless, its face a mess of buboes and suppurating blisters.

Organic-looking pipes, glistening with mucus, burrowed their way into deformed nostrils and the corner of the Marine's gaping mouth. Its exposed teeth were cracked and yellow, its gums raw and bleeding. It was almost as if the polluted atmosphere of the forge world was not polluted enough for the Death Guard to thrive in, and they needed to ingest their own foul distillations and necrotic gases to function fully.