Constitution represents your character’s health, vigor, and general conditioning. A Constitution bonus increases a character’s hit points, so the ability is important for all classes.

You apply your character’s Constitution modifier to:

• Each roll of a Hit Die (though a penalty can never drop a result below 1—that is, a character always gains at least 1 hit point each time he or she advances in level).
• Apnea, Endurance, Inedia, Running, and Constitution Profession checks. These are the skills that have Constitution as its key ability.
• Number of Disciplines and Skills a character begins with at 1st Level.
• Saving Throws versus Paralyzation, Poison, and Death Magic.

If a character’s Constitution score changes enough to alter his or her Constitution modifier, the character’s hit points also increase or decrease accordingly.