It all began years ago, during the Great Infection. A city in the Northern Territories district of Signet-A called Caspur was the source, a hospital in Caspur was the beginning, the Patient Zero. The infection spread throughout the highly urbanized area, the second-largest city in Aescentia. However, measures taken by Aescentia's finest scientists and doctors stopped the disease there.
What it was is this: The infection, dubbed the Sixin Disease after the last name of Patient Zero, was similar to Earth's Marburg or Ebola, in that it as a disease of the brain. Once it got into the body, it headed straight for the brain and began to subtly change it, mess with the chemical balances, making the infected insane and essentially zombified.
The story continues to modern day, almost seventy Signetian years later. Due to the pains taken in preventing the spread of the disease, Caspur had become quite isolated from the rest of the planet. Having lost more than half their population in the initial waves of the infection, they slowly grew, building hydroponic gardens for food and generally being obsessively neat and clean about things to ensure the disease stayed dead.
The disease also changed the Caspurians, making them look subtly different, making their brains work differently. They were taller than the average Aescentian, almost six feet tall on average, quite pale, and all of them had piercing red eyes. They became the epitome of OCD, making sure everything in Caspur was neat and orderly. For example: One of the laws of Caspur is that all lawns must be kept trimmed at exactly one and a half inches, punishable by death.
Due to the long-kept isolation, the Caspurians became very independent and resented being part of the larger empire of Aescentia. So, in the last Parliamentary Procedure, they filed for complete, sovereign independence from Aescentia. Due to their large population, just in the confines of the city, they quickly achieved quorum and the measure passed, effectively creating the City-State of Caspur.