One of the most dangerous parts of the world are the various afflictions that can affect your character, or characters around you.
Afflictions are affects that can potentially harm you over time, including inflicting you with conditions. Conditions change your state of being.
Think of them this way: an affliction is like a disease, an infection, or a virus. They don't strictly cause you any conditions, but you suffer conditions because of them. Getting the flu (affliction) can lead to exhaustion (condition).
Afflictions can cause conditions, but conditions cannot cause afflictions.
Afflictions are a multi-stage problem that afflicts your character, potentially causing additional harm over time. Afflictions will be listed in a card format, with some information.
The most common examples of Afflictions are Curses, Diseases, and Poisons.
At the top of an affliction card contains the affliction details. This includes the name, type of infliction it is, and the way to gain the affliction. Most poisons must be ingested, most diseases involve being close to a creature already afflicted, and most curses derive from magical effects.
When you are targeted with an affliction, you are able to make a Saving Throw. The Affliction will tell you the type of Save, as well as the DC.
Many, but not all, afflictions don't immediately affect you. Once you fail a saving throw, there is an onset period where you suffer no ill effects from the affliction. Think of this like an incubation period. You may get the flu from a co-worker at work, but you don't feel it's effects for a day or two after exposure.
In addition, the Max Duration is listed, this is the absolute maximum amount of time you can be affected by the affliction. Once this period is over, you are completely cured of the affliction, although you may continue to suffer longer-term consequences of it. Negative effects imparted to you by an affliction are handled separate from the affliction itself.
An affliction is divided up into multiple stages. Each stage will be listed with a few things: what happens to you when you reach that stage, and a new time.
When you fail your initial saving throw, after the Onset Period has passed, you gain Stage 1 of the affliction, suffering the listed effects of that stage, suffering no further penalties until the time listed in the stage passes. When this happens, you make a new saving throw, succeeding means you move down 1 stage, and failing means you move up 1 stage. If you ever reach Stage 0, you are cured of the affliction (unless otherwise noted). If you ever reach a stage higher than listed in the affliction, you stay at the highest stage, and suffer the effects again.
Note the following information on stages: any damage dealt by an affliction happens only once per failed saving throw. Thus, if you take 2d6 poison damage as part of a stage, and the stage lasts for 10 minutes, you only take the 2d6 poison damage once, not every round. However, if the stage lists a condition, that condition lasts until you lose that stage. Finally, when you increase or decrease a stage, you only suffer the effects of the stage you are on. If a condition is supposed to last through multiple stages, it will be listed on all stages.