White Scars - A New Threat: On Prospero, it was difficult to witness what had become of Magnus' iridescent city of glass and crystal. The Khan made his way through the layers of grey-silver dust, watching heavy skies scud across the blackened shells of old structures. The lightning never ceased, flickering away on the northern horizon. The Khan's keshig of Terminators fanned out around him. They went as warily as he, and their bone-white armour made them look like ghosts in the dark. Jhagatai had not wanted to believe it, not truly.His feelings about Leman Russ had always been mixed -- respect for the warrior; exasperation at the boasts, the self-appointed exceptionalism. It was another thing, though, to witness what he had done, to see the truth of the White Scars star-speakers' (astropaths) testimony.The Khan found that the truth, now that it was before him, was a bitter draught indeed. As the small landing party of warriors made their way deeper into the ruins of the city, they found themselves near the cult temples. As the Khan investigated the immediate area he heard an unmistakable buzzing noise, like the drone of massed insect wings. Though there were no life signs detected, the Khan could not shake the feeling that he heard a distinct buzzing sound.The Khan ordered his warriors to disable their auto-senses and to use their own eyes. Blink-dismissing the lattice of targeting reticules and environmental compensators hovering in their field of vision within their helmets, only then did the White Scars see them: shimmering in spectral blue-white, arthropodic, winged and massive. There were dozens, sliding up out of the ground like unquiet shades rising from the grave.They were ruined things, twisted and hunched, though still twice the size of the Terminators before them. Once free of the broken earth they swayed through the air jerkily, lurching as though blind and famished. The Khan recognised the vile creatures immediately -- Psychneuein -- vile Warp entities drawn to the mental emanations of unprotected, badly-injured or nascent psykers whose minds they attack for the obscene purpose of gestating their progeny.These creatures had been a blight on the otherwise benign world of Prospero for centuries, consuming the minds of mortals. The Thousand Sons had hunted them, driving them into the wilds and far from the glittering spires. Now, like everything else, they had been reduced to ghosts -- remnants of the living horrors they had been. Only, unlike all the other destroyed fauna, they had retained some vestige of their old wills.The White Scars quickly found that their physical weapons had no effect on the spectral insects, their blades passing through their arthropedal forms harmlessly. Their only advantage was that the creatures were blind, yet they could still sense their prey. When the Psychneunin struck, they angled their swollen abdomens to sting. The glowing tips of their long proboscis passed through the Terminators' Ceramite with ease.Howls of agony filled the air as lumpy matter was sucked up the creatures' translucent proboscis. Unable to fight such fell creatures, the Khagan ordered his warriors to fall back. As Jaghatai fought the hideous creatures, the ground beneath his feet gave way, the flagstones damaged by the Space Wolves' relentless orbital bombardment.Falling for a long distance, the Primarch came to a sudden halt. Buried up to his chest in the fallen debris, the Khan attempted to contact his Keshig on the surface. He received nothing but static for his trouble. Pulling himself free from the pile of rubble, Jaghatai found himself in a strange underground world of sink-holes and chasms that might open up into something bigger. He had come looking for caves. And he had found them.