Overture

In the unknown past of Planet Earth, there was an event called "Calamity". Well, there were many events throughout the history, but if one got titled with a proper noun, then it must be historically significant. In fact, nobody will think this "Calamity", a mass extinction even Permian-Triassic Extinction Event pales in comparison, is insignificant either in ecosphere or in "civilization-sphere", for it being a global apocalyptic tectonic hyperactivity of a prolonged duration, in forms of super-erupting volcanos and beyond-excessive earthquakes, suffocating and freezing all creation in a supreme environmental pollution followed by a long-lasting volcanic winter dubbed as "Long Cold", which lasted 150 years at minimum.

But life will find a way. Homo sapiens nevertheless prevailed for being ridiculously stubborn and adaptive, despite suffering the destruction of the vast majority of, if not all, settlements along with the associated population; and despite over 95% of other species, including many insects, were gone. As the planet itself calms down, pumping no additional volcanic ash or sulfuric acid into atmosphere; also as already-released ash and acids gradually fall back from stratosphere, allowing sunshine to disperse darkness and coldness, survivors of the Calamity slowly crawled from shelters to recolonize the world that never the same as before, and by this reason, they suspended the Christian Era, commonly known as "Anno Domini" or AD, replacing it with AC, "After Calamity".

By the year of AC 432, Planet Earth, although still largely being forsaken wastelands of post-apocalypse, is progressing well on the road of rejuvenation, local and global ecosystems are being restored, and new sovereignties had been established and are expanding to carve up the ever shirking "ownerless" territories, among them is Pacific Federation, or more formally "Federation of Pacific Rim" also simply "Federation", hailing from the Asian-Pacific Region, or just picture a glorified Roman Empire with Pacific Ocean as its Mediterranean Sea, and it do looks like a Roman Empire in After Calamity Era, vast in size and population, strong in economy and military, and controls a large portion of world cordium deposits. As the heaviest naturally occurring element, cordium is believed to have been hidden dormant in Earth's mantle for billions of years and directly responsible for the occurrence of Calamity, for sharing similar traits also exhibited by the Elerium 115 featured in the franchise of X-COM/XCom and Corium 276 featured in Submarine Titans, releasing a tremendous amount of energy, mainly in the form of heat/infrared but also extremely volatile/explosive, especially when being bombarded by neutrons, therefore its application is two-pronged according to these properties: Firstly "super-fuel" to energize specially designed radioisotope thermoelectric generators (RTG), and the power provided by a canister of cordium or a "cordium battery" even rivals a fission reactor of same size (if a fission reactor can be built that small) also can last as long as a chunk of uranium of same size; then, of course, "super-dynamite", enabling missiles and bombs to be smaller without shrinking lethality, if not making them more destructive. Undoubtedly, cordium is among the most demanded minerals in the world nowadays, and it's also not strange that Pacific Federation's prosperity is largely attributed to it. Unfortunately there are a number of groups on this planet feel the existence of the Federation is causing certain complications, and they intend to make sure its reign is short-lived.

Perils also lurk inside Pacific Federation, for the term "Federation" is merely nominal, it's actually a confederation for being a coalition of countries instead of a nation consisted by states or provinces, and as a de facto confederation, there are always someone sought to withdraw from the collective by whatever reasons and means they see fit, including secret collusion with anti-Federation factions worldwide. As in AC 432, some of these separatists and their international backers just can't wait any longer, and the story also begins here…