Xil is a desert world.
Xil once possessed a biosphere, one that gave rise to a sapient species. During this period, the world was visited by the xel'naga. However, a disaster struck the planet, wiping out its native ecology overnight. The xel'naga abandoned the world, though their relics still remained, along with those of the indigenous species.
Millions of years after the cataclysm, Xil's ecology had yet to recover. However, the world was not without visitors, such as the Tal'darim. In 2504, a Moebius Foundation expedition attempted to retrieve an artifact from a xel'naga temple, but were wiped out by the resident protoss fanatics. Raynor's Raiders made their own attempt, using the expedition's Drakken laser drill to burn through the temple's door, which doubled as a weapon against the Tal'darim's more powerful units. Raynor achieved victory in the end, but the Tal'darim Executor, Nyon, already enraged by Raynor's robberies of their prized possessions on Monlyth, said his crime would echo through the stars, causing Raynor to wonder if getting the artifacts was worth it, contrasting with Tychus Findlay's more mercenary attitude.