Plague / Epidemic
Humanity crumbles from a superbug known as the Morose affliction. This sickness is immune to all forms of modern medicine, an accumulation of mankind's neglect of antibiotic resistance. The Mobile Purification Unit rises.
The peak of human population, accumulating to a total of 8.7 billion people. Upon completing this milestone, the world population began to stagger at an alarming rate. A superbug immune to all forms of modern medicine unleashed upon society, causing mass hysteria and global unrest. Research is started into a potential cure, though little can be done to combat the lethal strain of a virus as it has developed antibiotic resistance.
With the fall of major world powers and society alike, the remaining scattered and few survivors look for any sort of order and hope. Their answer is found in the formation of several key factions.