Word of their expansion had reached our outer colonies, and several of our interstellar settlements had fallen before their ships were observed on the borders of the solar system. They were a militaristic race; sacking planets for industrial minerals and raw materials, purging most of the native inhabitants, keeping a few as slaves for their mines or as entertainment for their elites. Two alien races, both close allies of us, were destroyed by the conquerors, their cities ravaged and their populations killed or enslaved. Terrible methods of torture were employed by the Rénzú Empire to subdue the survivors; not only did the race use their victims for extracting wealth and resources, but they gained a sadistic pleasure from torture and oppression, and held a sense of superiority above all other species. Hundreds of years ago, we united with our alien allies to create a coalition of mutual cooperation and respect, but the Rénzú (as they call themselves) viewed other races as "animals", culling most of their victims but raising some for hard labour.
When they came to our planet, we had no choice but to resist; yet, their technology and industrial capacity was leaps and bounds ahead of us. They seized the industrial worlds at the edges of the system, destroying our ships and orbital defense forces and organizing ground invasions. After six planets and moons had fallen, the holo-networks were abuzz with horrific images of mass slaughter, warfare on ground and in space, and the cruel methods of torture and subjugation used by the Rénzú. Our military forces scrambled to surround and protect our homeworld, but the aliens used high-energy plasma weaponry to destroy our orbital intelligence networks and the few ships we could muster. Our plasma cannons were barely a tenth as powerful as theirs. As soon as they blockaded our planet, they propelled great bolts of plasma into our cities and urban centers, killing tens of billions and forcing many more to flee. I saw the horror of the refugee camps, the frantic crowds squeezing through the city streets in a desperate attempt to escape certain destruction. Those who were lucky enough to reach the countryside faced starvation, disease, and violence. Our infrastructure had nearly collapsed; the few ground forces we had left fought a futile battle against the great shuttles of the Rénzú that landed in the millions. Within weeks, with complete orbital supremacy and superior technology, the aliens occupied the planet. Parents were stripped from children; the few that attempted to escape the alien troops were killed (if lucky) or horrifically tortured; many billions were led to extermination camps for the slaughter.
I was among the 20% who were left alive as slaves. They led us to the mines, working many of us to death. My group had to produce daily quotas of Yttrium, a mineral used in their superconductors; others worked in mining different industrial minerals, or base metals like copper, aluminum, and iron. Those who did not meet their quota were tortured, killed, or mutilated to set an example for the others.
I managed to escape the camp, participating in a global insurgency against the occupiers. We sabotaged their factories, set explosives in their camps, destroyed their mines. I have killed more of my own through these acts of terrorism than Rénzú; nonetheless, I am devoted to ending their reign of terror through whatever means possible.
We rarely see the Rénzú themselves, their robots and automated troops doing most of the dirty work. They are a horrific sight; two long appendages supporting a bulbous body, with two arms and two hands, and two eyes mounted on a single head. Their very appearance seems a violation of Nature. Although they have ruled us for twenty years, their reign of our homeland will end, and we will prevail.
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"Rénzú" is Mandarin for "human".