We're Doomed

There were only a few cases to start out with and nobody thought anything of it. It would blow over in a couple weeks, right? It was nothing to worry about.
They said that four years ago.
Since then, the world has basically been overrun by these... these things. Former humans that roam the Earth, destroying everything in their past, not to mention the animal mutations that they brought with them.
But that's not all that's f*cked up with the world, oh no.
About a year into it, a man had a brilliant idea; fight the things using clones. It seemed simple, create mindless clones, designed to kill, without personalities. Surely that would win them back to world, right?
Not exactly.
While they proved to be excellent killers, they seemed to be lacking in the whole 'no personality or diversity' department. Once these clones adapted to have independent thoughts, they broke free, leaving the facility that created them.
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