The Cataclysm

The full magnitude of 'The Cataclysm' is never mentioned, though in the opening titles the surface is depicted as a post-apocalyptic scene, implying nuclear warfare. Earth's inhabitants, ecosystems, and species have been exterminated, save those that found sanctuary in an 'Oasis'. The skies immediately above the surface are ravaged by continuous lightning storms, dangerous air currents, and acidic clouds, known as the 'Warp Winds', through which the only safe passages are the hollow mountains known as 'Wind Pits'.