Prospero

Prospero was the original homeworld of the Thousand Sons Traitor Legion of Chaos Space Marines and their Primarch Magnus the Red.

Chosen by its settlers for the planet's isolated position (although far closer to Terra than many other colonies), Prospero only had a few redeeming qualities. It possessed no independent resources, little contact with any outsiders and only a few sources of nourishment. The only reason for planting a colony there was because it was a very good place to hide, and thus became a large community of psychically talented and often physically mutated humans who could find no refuge elsewhere in the galaxy.

During the Great Crusade, Prospero had developed into a paradise world. Many of the vast buildings on the planet were massive gold and marble pyramids. Propsero was a planet with blue skies and gleaming Egyptianesque architecture. One of the world's many cities was the capital city of Tizca, often referred to as the City of Light, where the Thousand Sons later held out against the Space Wolves when they were mistakenly declared traitors against the Imperium.

Prospero's 'cleansing' at the hands of the Space Wolves was hastened by the dilapidated state of the planetary defenses. As the homeworld of a Space Marine Legion, it was standard for the surface of such a planet to be protected by immense planetary defense lasers sunk into reinforced silos many miles beneath its settlements. Orbital fire platforms, automated tracking stations, minefields, as well as a number of the Legion's own starships – all were manned continuously and diligently.

The focus of the Thousand Sons, having always been away from the traditional Space Marine role of combat, and in most forms towards the use of sorcery and psychic abilities. This had led to a dangerous weakening of the Prosperan defense grid. The cavernous subterranean defense lasers were neglected, unmanned and poorly maintained and the orbital defenses were virtually non-existent. As a result, the arrival of the Space Wolves' battle barges went uncontested, their orbit-to-surface ordnance barrages unanswered and their drop-pods unchallenged.

Ironically, whilst the attack was underway, the Thousand Sons' focus remained on their lore – rushing to save what incalculably precious works of sorcery and psychic research they could whilst the righteous, if possibly misplaced retribution of Leman Russ' Legion went unchallenged. Indeed, had a defense of Prospero been attempted, more time might have been bought to evacuate the libraries and studies of their ultimately costly work.

The planet eventually became a blasted ruin, picked clean by millennia of looters and Rogue Traders, declared Exterminatus by the Inquisition because of its connection to the Thousand Sons and its people's heretical sorcerous heritage.