In 2544 YSB, the Dark Plague hit Bakieh. In the following months, the plague spread across the world. It hit the urban cities of Victellus and Terrosea hard, made only worse by a coinciding outbreak of Bylon's Pox that left many mages stricken down without their abilities. The following centuries were shaped by this quick and devastating event. 10% of the Sura Empire's population died, but the death toll was worse elsewhere. Nearly 50% of the population of Tulan died to the plague, devastating the continent. Politically systems teetered on the edge of collapse and for a while, it looked as if the empires built up over centuries might be bought down in days. In its aftermath, the Sura Empire quarantined its borders and global trade slowed for years. It was this event that began to stir the xenophobia that would grip the empire in the following centuries, as its people - and especially its leadership - became increasingly distrustful of the outside world.
The cause of the Dark Plague was never ascertained. It was fought by some to be a supernatural curse, others to be a divine retribution. The limited medical understanding of the time was unsure how to classify diseases, and had rarely seen such outbreaks. Magic could heal many things, but the Dark Plague proved largely immune to magical countermeasures.
The symptoms of the Dark Plague are the reason for its name. The affliction begins with a darkening of the eyes, which then causes the veins of the victim to turn black and strongly visible against their skin. It progresses quickly, leading to coughing up blood within the first 24 hours, then a fever and intense sweating. If the victim does not recover, it will eventually lead to death within two to three days. It can be slowed by a poultice of herbs, and many victims will recover, but it has a fatality rate of around 30%.
The Dark Plague is largely immune to magical attempts to heal it, as a viral disease. However, magic can be used to ease the victim's symptoms and increase the rate of survival exponentially. Poultices of herbs, bed rest, and lots of liquids are the only other methods available to treat the disease. It is highly contagious, and so presents a contamination to those trying to treat it. Victims are usually quarantined for the safety of the general populace.