Disclaimer: I do not own FMA.
It is always a surprise to travelers to come to the World to hear that they know of the desert. Surrounded by a seemingly endless landscape of forest and mountain, they would think this not to be the case. Yet every inhabitant of the secluded village, even the youngest child, can tell them what the desert is like. When asked how this is, the villagers grow cold to the outsider, making it very clear how alone they truly are in the World.
Yet a young boy with many faces is always willing to explain this. The travelers always mention him in their tales of the peculiar village in nowhere, and never stop to wonder how the same boy is always referred to even though word of the desert-knowing village and the secret-revealing boy has always been a boy despite the relative age of the story. It seems as if the World is so isolated that it even follows its own course of time.
To the travelers, the boy will tell of how a wind will sweep over the World every spring from the east, carrying with it the heat of the desert day and men of sand wielding guns that spit fire back from whence they came as they are whipped off to return next year. He hesitates at the mention of fire, turning his face ever so slightly to his audience, and at this they see its marred flesh and ravaged eyes before a curtain of black falls to cover them once more.
He claims that, chasing the wind is a heavy downpour that brings with it a ghostly mist that lingers in the forests, finding sanctuary there away from all that troubles the world. It had not always been this way, the screaming wind that rampages angrily over the lands it passes and the accusing rain, along with the mist that every year seeks shelter in the trees before moving on to chase the wind. In fact, it is a very recent thing.
The boy then turns around to face those that listen to him dead-on, and his mutilated face splits into a Glasgow smile, revealing metal teeth. Rust spots the chipped surface of them, along with blood and sand.
The travelers hurry away at the sight of this, and know that the World's days are numbered.