Today, the desert is a wilderness to be reclaimed, not an advancing force of nature, and when man touches the desert it is to irrigate. This has not always been the case, for history tells of a civilization which turned a rich river valley into a barren desert by training far too many Flareon.
Flareon have long been a popular pokemon to train; their mannerisms are commonly considered adorable, and although not the most powerful pokemon, they are effective enough at defending trainers from wild pokemon to act as guards. In the Orre Valley, then rich in fire stones and Eevee, they became popular, even fashionable, until they were as common as Hoothoot and Rattata.
As their population grew, a devastating drought spread throughout the land, bringing famine everywhere. This sparked investigation of the climate, and it was soon found that while the headwaters were fine, the Orre river itself was evaporating. The large concentration of Flareon, with their immense body heat, had overheated the river and the soil might as well have been desert sands for all its nutritional content. Upon news of this, some trainers killed their Flareon in rage or sent them to other far-flung lands, but most could not bear to part with their pokemon or their homeland. The people starved, the land turned to desert, and the survivors left their cities, forced into nomadism by their own pokemon.
Today, Orre's capital is called Phenac, after an old name for Ho-oh, for their civilization perished in flames and seeks to rise again. Orre today is a chain of cities in a vast desert, and the cities are small and often harassed by Flareon trainers raiding them for food. It has not yet rose again.