The apocalypse, called the Collapse, was caused by a number of factors. To understand everything and keep all our ducks in a row, we must first talk about Project Rainwall. The US government was experimenting with human-animal dna hybridization in an attempt to enhance soldier capabilities. This was all done from a secret underground facility known as Facility 42, located deep underground at Fort Carson, Colorado. The soldiers involved in these experiments were volunteers, however, they did not know what they were getting themselves into. The experiments involved much more than just DNA modification. The experiments were a combination of that, surgical procedures, and some think even nanotechnology was attempted.

In the process, some of the test subjects rebelled against their treatment, and staged a breakout from the Facility with plans to exact retribution on those in charge of the program. Having newly gained abilities helped, as did one of the officers involved in the program, who aided their escape.

What was unknown at the time, however, was that the DNA modification serum had activated a dormant strain of chicken pox in one of the test subjects, which mutated like its host. When the test subjects escaped, they inadvertently released this supervirus into the wild, which eventually spread and killed many of earth’s human population.

Society collapsed into chaos, and now many survivors still struggle to navigate the wreckage. In addition to contending with the environment, the virus, starvation, and other survivors, they must also now contend with these human-animal hybrids.