The sand underfoot had bathed in the smoldering rays of the sun for the whole day. The entire ground radiated heat in rippling waves, distorting the horizon and purging the sky of the few clouds that remained. Had there been tumbleweed in that desert, even they would have held their ground against the feeble breeze. Both flora and fauna were absent from those hostile sands--not to anyone's surprise. To the North and South rose vast mountain ranges looming over the desert and stabbing the sky with their snowy peaks; to the East and West more desert lay, as far as any eye or looking glass could see.
In these sands maundered the frame of a spavined automaton. It wore a tattered sackcloth that frayed near the machine's rusted knee-joints. A crudely made staff aided the metallic creature as it shuffled through the vast desert, hunched over and sand-scratched, torn tied rags and bandages covering any circuits and vital innards they could. The machine had wandered for an age, and for ages more it would continue to do so. And for all those ages, it would never cease to think about what it once was.
In its zenith the machine had stood seven feet tall, and weighed a full ton; it was impeccant power, with the look of a man. Its frame was built with carbon nanotubing, and its steel body was coated in a deep aubergine paint job. The machine had the strength of a thousand men, and the conation of ten-thousand more. It was bulletproof, fireproof, waterproof, shockproof, and freeze proof; but time proof was something it was not.
Now it was, almost literally, a shell of itself; its once gleaming eyes were scratched and dull and its once polished head now resembled a fractured skull. Its left arm and torso were a skeletal framing, strung with wires and chipped metal. A millennia ago, its mouth had stopped working; two centuries later, its voice box followed. Four more centuries passed, and its joints and orifices became clogged with rust and arenaceous material from the desert. It found its home here, in the purdah of the desert caves. It lived in solitude; no one to talk to, no goals to satisfy, and nothing to do; so like an anchorite, it sat, and it thought about its past.
It recalled flinders of memories; it saw a grand king sitting in a throne of jewels, commanding the automaton to kill. A small girl looking up at the machine, crying, trying to tug it by its hand towards some unknown goal. There was an old woman's heartbeat slowing as she took her last breath. The harsh bark of a man clad in battle scars and a military uniform. It saw many faces of those it had served, those it had lived with and spoke to. As it retrojected its memories, it saw the reactions of the humans it had served; the facial expressions the humans made, often accompanied with a coloration of the cheeks. The automaton watched as tears flowed and smiles spread; as screams of rage pounded its eardrums, along with sighs of heartsease. As it examined these memories, these emotions, it began to understand, to apperceive.
The rusted machine thought of The End, the night that the superpowers launched the warheads and effectively put the quietus to the majority of the human race. Perhaps some lonely tribes continued an existence in the extremes of planet Earth's environments, but it was likely that the radiation had killed them off as well. And as it thought about this, about The End, it felt; for the first time in its existence, it experienced emotion. It experienced the loneliness of an age in solitude; the grief for the loss of its creators, of its purpose. But the emotion that it suffered most was the sorrow and agony, the pain of realization.
The realization that it had followed its orders to perfection; that it had, without question, pushed the launch button.