Thousand Sons - The Fall of Prospero: When Magnus the Red learned of Horus' betrayal of the Imperium and his decision to give his loyalty to the Ruinous Powers, he used his own psychic abilities to get a message to the Imperial Palace on Terra by directly contacting the Emperor mind-to-mind, though this ruptured the Palace's considerable psychic defenses and killed thousands of people whose minds were unable to handle Magnus' potent psychic call. But the Emperor refused to believe that His favorite son Horus would ever betray His trust and so He assumed that it was Magnus who had been corrupted by the Chaos Gods since he was once again using the sorcerous powers that had been banned by the Council of Nikaea. Believing that Magnus sought to sow dissension in the Imperium to serve his masters in the Warp, the Emperor ordered the Space Wolves Legion to go to Prospero and bring back Magnus to Terra, so he could give account for his actions. But this was not to be, as the corrupted Warmaster Horus had intercepted the Emperor's communique with Russ' Legion and subtly manipulated their orders. Instead of just arresting the offending Primarch Magnus for his transgressions and bringing him back to the Emperor for censure and punishment for breaking his oath never to use his psychic powers again, Horus changed their orders to read that the Space Wolves were to assault the Thousand Sons' homeworld of Prospero. Magnus had psychically foreseen the Loyalist Marines' attack on Prospero, which was eventually carried out by the Space Wolves Legion, elements of the Emperor's Adeptus Custodes, and millions of Imperial Army troops, all assisted by the Sisters of Silence acting as psychic "blanks" in order to nullify the Thousand Sons' psychic abilities.Magnus had finally understood, after his forced psychic entry into the Hall of the Golden Throne and his direct mental communication with the Emperor, that he had been manipulated by Tzeentch, with whom he had apparently unknowingly consorted with while desperately looking for a way to stop the emergence of the psychic mutations that were threatening to destroy his Legion. In an act of repentance and sacrifice, and to show his father that he and his Legion were loyal to the end, he did not warn the defenders of the planet or his Legion of the coming Imperial attack, on the contrary, he imposed a psychic veil on the planet so the Thousand Sons would have no clue of the impending assault. He also dispersed the Thousand Sons' Legion fleet far away from Prospero. He knew that Tzeentch wanted the Thousand Sons and Space Wolves to slaughter each other, and he wanted to stop these plans, even if it meant the sacrifice of his Legion and homeworld. Therefore, the Space Wolves' attack on the Thousand Sons' homeworld of Prospero came as a complete surprise. Because there was no warning, the invading fleet translated from the Warp into realspace practically on top of the planet, and quickly destroyed its orbital defences, initiating the great campaign of the Horus Heresy known as the Fall of Prospero to Imperial historians.Then, a tremendous orbital bombardment reduced Prospero to cinders, except its capital, Tizca, a beautiful city and the seat of Magnus and the Legion, that was at all times protected by a psychic void shield. This shield was maintained by one of the Thousand Sons' cults, and Magnus did not disable it, knowing that such action would alert his Legion. Because of the shield, an Imperial invasion of Tizca had to take place. A huge force of landing vehicles and support craft descended on the city, whose defenses had been left mostly unmanned. Establishing a beachhead in the spaceport area, the Space Wolves began slaughtering thousands of Prosperans and burning everything in sight. Yet the Thousand Sons' rank-and-file did not share Magnus' acceptance of defeat and punishment, so they took up arms against the Loyalist invaders. The Thousand Sons managed to hold Tizca (the only surviving city on the planet) for a period of time before they were eventually pushed back. Magnus eventually, reluctantly, took to the battle against the Loyalist forces when Leman Russ and his Wulfen were unleashed on the last standing Pyramid of Tizca. Magnus and Leman Russ took part in a devastating duel in which Russ was ultimately victorious. Magnus invoked ancient sorceries in order to escape Prospero by opening a gateway through the Warp into the Eye of Terror where a Daemon World had been prepared for Magnus and the remnants of his Legion by their new patron, Tzeentch. Magnus was subsequently "rewarded" by Tzeentch by being transformed into a Daemon Prince.Following the siege of Prospero, the Thousand Sons have been the arch-enemies of the Space Wolves Chapter. They have tried several times to uproot and destroy the Space Wolves, including establishing a Chaos temple in a mountain spire on the Space Wolves' homeworld of Fenris, a temple to Tzeentch known as the Daemonspire whose creation was ordered by Madox, a high-ranking Chaos Space Marine in Magnus' service. The Thousand Sons tried again on the world of Garm by stealing the Space Wolves artefact known as the Spear of Russ to perform a sorcerous ritual that would transform the planet into another Daemon World of the Warp. Even though the Spear was lost, the world was saved from Chaos and retaken for the Emperor by the Imperial Guard. In this instance, Ragnar Blackmane defeated Madox and cast the Spear into a partially manifested Magnus, losing the Spear but banishing Magnus back to the Warp.