Different attacks and other harmful effects deal different types of damage.

Acid: Exposure to any extremely acidic or caustic compound can cause acid damage, including exposure to highly alkaline substances such as lye.

Blunt: Bludgeoning attacks—hammers, falling, constriction, and the like—deal blunt damage.

Cold: Tissue damage caused by extreme cold, typically from the environment or from magical attacks.

Entropic: Entropic damage causes the rapid breakdown of structures, including flesh.

Heat: This sort of damage can be caused by flames, by extremely harsh light, or by direct application of heat.

Impaling: Puncturing and Piercing attacks, including spears and monsters' bites, deal impaling damage.

Kinetic: Kinetic is pure energy focused into a damaging form. Most effects that deal kinetic damage are spells.

Lightning: Any high-voltage source, either static or current electricity, can cause lightning damage.

Mental: Psychic abilities, fear effects and illusions deal mental damage.

Physical: This is a 'meta-type' of damage, that encompasses Blunt, Impaling, Kinetic and Slashing.

Poison: Venomous stings and toxic gas deal poison damage.

Slashing: Swords, axes, and monsters' claws deal slashing damage.

Thunder: A concussive burst of sound, such as the effect of a Thunderbolt spell, deals thunder damage.

Vital damage is a special case. Attacks that inflict Vital damage typically have some magical component, or are the result of considerable skill. It represents selecting the best sort of damage to use against the target, whatever that might be.

Vital damage can never be selected for Resistance or Vulnerability. It bypasses all armour effects, including Damage Reduction. Unless an effect specifically states that it reduces Vital damage, there is nothing that can protect the target from this sort of damage! The only good news is that it can be dodged, so it still applies to stamina first, not directly to hit points.

Sometimes, damage will be listed as non-lethal. For example, some weapons are noted for inflicting non-lethal damage. Non-lethal damage cannot kill an opponent, but it can take them out of a fight easily enough.

Non-lethal damage is applied to stamina, but does not apply to hit points. Any non-lethal damage that would be applied to a character's hit points instead inflicts a penalty to their Capacity saving throw. This penalty is equal to the amount of damage that would have been applied to hit points, and is removed after the character makes their Capacity saving throw. A character who takes multiple such penalties applies only the highest penalty.