A plague is the spread of deadly sickness throughout a large group of people. When the life stream is burdened by too much corrupted magical power, instead of recycling the mana, its sent out into the world in the form of a plague. Three plagues have hit Valmasia, the most devasting having wiped out a third of the population.
- All creatures can be infected and die due to it. This extends to nature: during an especially bad plague, greenery will turn brown, crops will bear no produce, and the rivers will dry up. Extreme weather effects can also occur, from country-wide freezes to heat waves that can last several months, meteor showers, and poison gas.
- Strong Magi may be able to survive being infected, depending on their magical power. This isn't the same for the peasant class, who have an especially low chance of living after being infected. Once infected, the person will rot from the inside, fall into madness, and die a slow, painful death.
- Most plagues will affect at least twenty percent of the population, and more often than not, much more. They can even spread outside of a village and take ahold of an entire country.
- When caught by the illness, most end up bedridden and unable to cast any sort of magic. Further symptons include vomiting, loss of senses, hallucinations, and a deadly fever. Eventually, the flesh itself begins to rot until the person dies by infection.
- Holy Magic is able to lessen the effects of a plague to a certain degree, but cannot be relied on to cope with a large number of people and will rarely rid a person of the illness. It may allow them to survive, though.
- If a star in the sky turns dark red instead of the usual bright orange, this means that it's overwhelmed by corrupted magical power and signals that a plague will soon occur somewhere in Eternia. A key role of an astronomer is to predict where the plague will take place and at what date.
- All negative action contributes. Dark magi in particular are key contributers, as they are often prone to depravity and tend to have corrupted souls.