Where does this story start?
Cataclysm DDA is a huge game containing content beyond belief, but where does it all start? What caused the apocalypse? The zombies? The mutants? All the horrifying creatures that want to ruin your day? And oh my god is that a Gigantic Naked Mole-Rat? Why are you still here? What is there to accomplish? Well, here you can learn about the world.
The Big Ka-boom
The game starts, by default, five days after the "cataclysm" that destroys the world. The game takes place in America, in a year between 2040 and 2049. The government of America is reckless with its people, and America could even be considered a dystopia. While the life of an average person isn't altogether bad, despite problems with the governments of countries like Russia or China, things aren't too bad. Evacuation shelters were built by the government to help improve the morale of the people and also worry them into continued support.
Ooey Gooey Mutants
Nobody is sure where exactly the XE037 came from, but they do know it comes from some plane that isn't our own. When scientists started discovering and learning to create portals to these different planes, they found a sentient type of organism they called "the blob", or XE037. What they do know, however, is that the scientists of America were experimenting with it. The XE037 is a kind of cell that come to together to create an ooze that can take many forms, such as turning humans into the zombies of the caltaclysm. However, the blobs can also come in more advanced forms. While these creatures came from the ooze that plagued humanity, they don't share its versatility anymore and are locked into their form, however, they are not unable to undergo further development. The blob mutates and continues to grow in host bodies, and can cause mutations in the zombies we see. The Zombie Hulk is one of these cases, a huge zombie that is as strong as a tank and almost as hard to kill. These cells, however, are not altogether hostile. Despite being the main part of humanity's problems with zombies, the cells can also grow in humans, and are what allow for extreme mutations, or even just a slightly better tolerance for things. Our scientists have managed to form them into "mutagen" to try and control mutations to benefit humans. Other types of creatures, such as the Triffids and Fungals, are from similar planes, however they aren't from the same. Because their reality is closer to our own, from what the scientists have found, the Triffids and Fungals are better able to survive in our plane than the XE037, which needs host bodies to survive for long.
The Trees Are Watching
Triffids are, by far, the most complex and intelligent of the three main types of creatures from the subprime planes. They have multiple complex languages, long with multiple types of communication. They enjoy a strict hierarchy of many disparate and unrelataed organisms that coexist under the control of the triffid hearts. Triffid colonies can "go feral" if the triffid heart controlling them is killed, much like a country without a leader.
It's Not Just The Trees
Fungals, or the Mycus, are a vast, collective fungal intelligence, connected much like fungus of our world. Similar to the Triffids, and unlike the XE037, the Mycus found Earth to be habitable and have started to rapidly spread across the planet, sending spores to colonize and terraform the planet as their own. They Mycus have met the Triffids before, from what we know, and have even been under their contol. However, the faction we have on earth are a "wild" group of them, and the Triffid seek to exterminate them like a weed.
What The Hell?
Unlike the others, a less successful vier for our planet is the Nethereum. Coming from another subplane, the Nether, the Nethereum are eradic and they come in all shapes and sizes. The Mi-go, kreks, flaming eyes, and many more are among these. Some of the Nethereum haven't found coming to our world quite as easy as the Triffids or Mycus, and many of the "lesser" Nether creatures cannot stand the environment for long. However, they can be just as dangerous as the other types of other-worldly beings, many have powers unlike anything humanity has ever seen, or in some cases, can even comprehend.