Prospero is the enlightened jewel of the XV Legion and the homeworld of the Thousand Sons before the Burning of Prospero. Once infamous for warp predators and psychic horrors, it was transformed by Magnus the Red into one of humanity's greatest centres of learning, philosophy and psychic scholarship. Its cities combine impossible beauty with disciplined arcane architecture, where crystalline towers overlook tranquil seas and libraries hold knowledge gathered from across the Imperium.