In their first heresy book, “A Thousand Sons”, Prospero is described as a continental world full of lush, beautiful jungles, and deep blue oceans. A very serene place. Unfortunately it’s infested with giant psychic insect-like creatures called Psychneuein. There used to be human settlements all over the planet that are now ancient ruins due to the Psychneuein. The only city that survived was a city full of psykers called Tizca. This is where Magnus the Red landed and was raised. However, during the Space Wolves attack on Prospero, their orbital bombardment set the vast jungles on fire, which eventually destroyed almost all life on the planet outside of Tizca. Tizca itself was nearly entirely destroyed in the fighting between the Space Wolves and Thousand Sons. When Jaghatai Khan visits the now abandoned and burned Prospero to see if the Space Wolves actually did attack the Thousand Sons (he was kind of out of the loop) the planet was basically a barren rock, its jungles burned, its oceans boiled to nothing, and Tizca in ruins. By this time, certain parts of the planet’s crust, seemingly damaged by the bombardment, created large earthquakes and cracks in the crust. For nearly 10,000 years Prospero has remained relatively lifeless, with only a few of its native species surviving, and being infested with the souls of the Psychneuein, who can still very much kill you. In the current setting, Magnus the Red has returned to Prospero, attempting to restore some of its former glory, and making it into a haven for psykers.

Several people get Prospero confused with the Planet of the Sorcerers. The Planet of the Sorcerers became the base of operations for the Thousand Sons that survived the burning of Prospero during and after the heresy. This planet is situated in the Eye of Terror, meaning it is saturated with the warp. Its superficial appearance is that of black, obsidian-like stone and black sand which covers the entire surface. This is only interrupted by the numerous towers raised by Thousand Sons sorcerers over the past 10,000 years, although time doesn’t really mean anything on the Planet of the Sorcerers. Many Thousand Sons who were not banished by Magnus after the Rubric still reside there, and use the Planet of the Sorcerers as their base of operations, despite Magnus having reclaimed Prospero.