The Yellowstone Supervolcano Remade The World. This event destroyed much of the US, accelerated climate change, blanketed the world in magic, and caused a massive economic apocalypse. The results of this event still echo today.
The full report is available from the USGS, detailing global impact.
Magic Rained From The Sky Like Golden Fallout. Hard Gold. Hard Magic. Gold-236. This metal was locked in the center of the world, its origin the subject of ongoing debate. Apparently an isotope of gold, it disrupts the laws of physics in a way that can only be described as magic. Many believe it to be the mythical metal known as orichalcum, that decays to mundane "soft" gold. As a result of the supervolcanic eruption, particles of this metal made its way into the food and water supply around the world, although the heaviest concentrations were in North America.
Hard Gold Is Magic. The metal is as strong as steal and can be used to create fantastic devices and objects. Its properties have made it the most valued metal on Earth. Some people, and even creatures, have evolved the ability to convert their personal energy to create magical effects shaped by their will.
North America Is The Center Of Magical Research. As society began to reform the importance of magic became clear. Megacorps established research arms to understand this phenomenon and magic represents one of the few ways someone from the street can make their way into an arcology.
Life Has Changed. The magical aftermath of the eruption altered the physiology of all life on the planet. Fantastic mutations have appeared in all forms of life, including humans. This has caused even greater stratification of society based on appearance.
No Country For Any Man. Rural society can no longer sustain itself and all people had to flock to the cities to survive. What farming is done today is completely automated in well guarded facilities. Even cities as large as 100,000 people or more that had no significant academic or industrial base were abandoned nearly overnight, soon to be overrun but all manner of mutants.
Profit Is King And So Are The Megacorps. These corporations will stop at nothing to make money and maintain their status.
Society Is Poisoned. Literally and figuratively. Sharing is out, taking is the norm.
Post Scarcity Only Applies To The One Percent. The beneficiaries of corporate success want for nothing while the world toils without hope day to day.
Transhumans Are The Face Of The New Order. These are the gengineered and augmented leaders of society, living lives of luxury in their secure Arcologies.
Mutation Is The Norm. Much of humanity has been radically altered by magic that the only standard was what it means to appear human is perpetuated by the Transhuman population. Anything is possible in the form of a mutation, although the most radical mutants cannot function in society and find home only in the Midwastes or the abandoned cities that dot the landscape.
Cybernetics Are Common And Powered By Hard Gold. A small bit of hard gold can provide enough power, in conjunction with an individual’s own energy, to allow perpetual operation.
Cybernetics Replace Negative Mutations. The increased use of cybernetics can be directly correlated with the replacement of any deformities as the result of mutation. This has made the use of cybernetics not only acceptable, but even fashionable.
Government Has Become A Trade Federation And Has Privatized All Public Services. The government can no longer control the megacorps. All public services are provided by Megacorps based on their geographic areas of interest, and can vary wildly. However, all of them come at a price, exemplified by trading one’s vote for subsistence.
The Midwastes Are A Barren Wasteland Of Ashen Concrete. The Midwastes cover most of what was once recognized as the Midwest.Chicago struggles on the edge of the wastes, and the Mississippi once again has become a great barrier. Where ashfall was 10-30cm or more, much of that turned into magically radioactive concrete after the first rains. Concentrations of orichalcum have crated superphysical anomolies that warp reality. Animals have mutated to survive in this blasted landscape to guard the treasures of a golden age of civilization that the dregs of the sprawl can now only dream about.