Vitality represent the amount of physical punishment a creature can take before it dies. A creature calculates their Vitality using the following equation:
When a creature’s Vitality drops to half or lower, that creature becomes wounded. When a creature is wounded, it gains the staggered condition until it is no longer wounded. Furthermore, when a creature is wounded, if that creature takes any standard or move action on its turn, its remaining wound points are reduced by 1 and it must make a DC 10 Constitution check. If the creature fails that check, it falls unconscious.
When a creature reaches 0 or fewer wound points, it is dead.
Wound Points and Constitution Damage, Drain, and Penalties: A creature’s wound points and Constitution score are intrinsically linked. For each point of Constitution damage a creature takes, it loses 2 wound points, but this damage does not affect the creature’s wound threshold. When a creature takes a penalty to its Constitution score or its Constitution is drained, it loses 1 wound point per point of drain or per penalty for the duration of the penalty or drain. A penalty to Constitution or Constitution drain has no effect on the creature’s wound threshold.