Psychneuein - Prospero Strain: The final strain of Psychneuein positively identified by the Ordo Xenos is the long-extinct Prospero Strain that resided on the now-barren homeworld of the Thousand Sons Space Marine Legion. These creatures were also insectoid and utterly repellent to the Human eye.Prospero's ancient capital city of Tizca was the last outpost of Human civilisation on that world, after its prior society had been wiped out thousands of standard years ago by the predations of the Psychneuein. Tizca was a city where the survivors of a planet-wide cataclysm found refuge from the assault of the Psychneuein.The Thousand Sons always suspected some freak upsurge in the Warp triggered an explosion of uncontrolled psychic potential within the Prosperine population, driving the Psychneuein into a reproductive feeding frenzy. The civilisation of Prospero collapsed and the survivors fled to the city in the mountains.For thousands of Terran years, the people of Tizca endured, while all they had built in the millennia since leaving Terra fell to dust. The surface of Prospero was dotted with the remains of their dead culture. Empty cities were overgrown with forests and vines, the palaces of their kings overrun with wild beasts.The survivors survived by salvaging knowledge and equipment from the destruction to construct techno-psychic arrays and sustainable energy sources, which then allowed them to build giant hydroponic gardens deep in the caverns of the ventral mountain ranges. They survived the Psychneuein threat by further developing the very psychic powers that made them so vulnerable.The Psychneuein were drawn to Tizca in their thousands, but the survivors were able to train their most gifted psykers to use their minds to erect invisible, telekinetic barriers of pure thought (known as "kine-shields"). They were primitive, bombastic powers compared to the subtle arts later employed by the Thousand Sons, but they kept the creatures at bay. Even so, the practitioners of the mysteries remained locked in their limited understanding of the Immaterium's power until the coming of the Thousand Sons' Primarch Magnus the Red.When Magnus came to Prospero, it was said that a great comet had borne him to the ground, for the impact he had on them was as great as his impact upon the planet's crust. The Tizcan commune, which was the name the survivors of the Psychneuein assault on Prospero gave to their little enclave, was a place rooted in tradition, but they had some skill in wielding the power of the Immaterium.Of course, they did not know it by that name, and the powers they had, while enough to keep the psy-predators at bay, were little more than the enchantments of idiot children. The young primarch was schooled in the ways of the commune, and he quickly learned everything they had to teach.In truth, Magnus had outstripped the learning of their greatest scholars within a standard year of his arrival. Their teachings were too dogmatic, too linear and too limiting for the potential of a primarch's mind. His intellect was superior in every way to those that taught him. With his teachings, he knew they could be so much more.To increase his understanding of his powerful psychic abilities, Magnus took a walk into the desolation of Prospero. True power comes only to those who have fully tested themselves against their greatest fears. Within the commune, the primarch knew no fear, no hunger or want and had no drive to push his abilities to their full potential.Magnus needed to be tested to the very limits of his powers to see if he even had limits. Out in the wilds, Magnus knew he would either find the key to fully unlock his powers or die in the attempt. A standard year after his coming to Prospero, the primarch walked from the gates of Tizca and marched into the wilderness for nearly forty solar days.Through his observations, Magnus learned to harness his powerful abilities during his long trek. He also met Amon, the future captain of the Thousand Sons' 9th Fellowship. Despite their discoveries, as was the way of history, nothing of import was ever achieved without bloodshed. Tragedy soon struck Tizca in the form of the return of the Psychneuein menace.Temporaily lax in their mental discipline, the Psychneuein were drawn to the large commune of psykers in Tizca in their thousands, blackening the sky with their numbers as they descended like a plague from ancient times. They swarmed from their darkened caves, organically shifting clouds of deadly clades, the relentless buzzing of thousands of crystalline wings representing the sound of inevitable doom.The males swarmed in, a hurricane of snapping mandibles and tearing claws, and fifty men died in the time it takes to draw breath. Behind the males came the females, engorged with clutch upon clutch of immaterial eggs. Their furious reproductive hunger was insatiable, and dozens of the primarch's friends fell to their knees in horror as they felt the psychneuein eggs take root in their brains.The beasts swirled around them, battering the Prosperines with psychic thrusts, scrabbling at their mental barriers to seed their minds with their eggs, and only the strongest of them remained. Amon and eight of the masters of Tizca stood with the primarch, and as the Psychneuein attacked again, Magnus knew this was what he had been seeking all along, a true test of his abilities. He would finally discover whether he had limits. Magnus would see if he was the master of his powers or was to be found wanting.As the Psychneuein came at the Prosperine defenders again, something magnificent happened. The primarch felt something move within him, feeling changed, as though an immense power that had lain within him, dormant and untapped, surged to life. As Magnus contemplated the moment of his death, raging fires erupted from his hands.The primarch hurled torrents of flame into the sky, as though he had always known he had such powers, and smote hundreds of Psychneuein to ruin with every gesture. Soon, the other Tizcan masters displayed hence-unknown abilities as well, as walls of flame sprang up at their command. Others were able to pluck beasts from the air and dash them on the rocks with the telekinetic power of their minds. Still other defenders were able to will the vital fluids within the Psychneuein to boil within their exo-skeletons.Amon saw images of the future and imminent danger seared though his mind, and he cried words of warning to his fellows, telling them of dangers to come and of how they might avoid them. Some of the other defenders sensed the lust within the Psychneuein to plant their psychic seed within the Humans' minds, the relentless animal hunger that drove them to feed and propagate. They reached into the minds of the beasts and twisted their perceptions so that they became blind to the Humans' presence.With these newfound abilities, the later psychic Cults of the Thousand Sons Legion were born. The threat of the Prospero Strain of Psychneuein was forever after rendered inert.