Vitality
Typically used with: Endurance.
In short: stay healthy. The Vitality skill is used when a character is fighting off disease, poisons, tranquilizers, and sickness. This skill essentially represents your ability to flex your immune system and physical composure. If you want to get on all of the carnival rides, even the spinning ones, Vitality is for you.
Healing
A character heals an amount of HP equal to the sum of their Endurance and Vitality for each full night of rest. No roll is required.
Resisting Infection
You can make a Vitality check to ward off disease. Each source of infection has its own DL — the higher the DL, the more virulent the infection. Some diseases are spread through touch, others through injury and direct contact with the blood, and others still are airborne.
If you meet or exceed the DL, you remain healthy. Otherwise, you gain the infected condition and assume Knockout penalties (see the "Diseases" entry in the Damage and Death section of Chapter 4: Life and Death). Every day you remain infected in-game, you have to make another Vitality check. If you succeed, you may ignore the effects of the disease for one day. If the player makes two consecutive, successful checks she is considered to have beaten the disease.
Characters can use the Craft skill to create medicine that helps your immune system fight off infection.
Resisting Poison
You can also make a Vitality check to tough out poison. Each poisonous substance has its own DL — the higher the DL, the more toxic the poison. Some poisons enter the bloodstream through injury, some must be imbibed, and some can simply be absorbed through contact with the skin.
If you meet or exceed the DL, you resist the poison. Otherwise, you gain the poisoned condition and begin taking a set amount of damage each round (see the "Poisons" entry in the Damage and Death section of Chapter 4: Life and Death). Every round you remain poisoned, you make an additional Vitality check. If you succeed, you can ignore the effects of the poison for that round. Each poison has a set duration.
Characters can use the Craft skill to create an antidote, antitoxin, or antivenom capable of counteracting the poison coursing through your veins.
Resisting Nausea
Vitality is also used in those unfortunate situations where your character needs to keep his lunch down or his pants stain-free. The circumstances for these challenges are as varied as their effects, so the DLs are variable.
Resisting Spells
Certain spells call for a Vitality check to resist, for instance Disease, Poison, and Sicken.