Characters can suffer damage of three main types:
Further, injury damage belongs to one of three subcategories:
Each of the three main damage types is tracked separately for each character; if a character suffers "3 fear damage", add 3 to their current total of fear damage. In the case of injury damage, all subtypes are combined together (but at the time of assigning damage, some additional effects may occur depending on the subtype).
Each character has a breakpoint for each of the three damage types. When a character has suffered enough damage of that type that they have reached or exceeded the breakpoint, the character will gain a condition. The details of which are described in each of the damage types.
Each character may have an armor value for each damage type; in this case, subtypes of injury damage have their own armor types (therefore, there are 5 possible armor types a character can have: physical, poison, magic, fear, and confusion). If a character would suffer damage of a certain type, reduce that number (to a minimum of 0) by their associated armor value. Mortal characters typically only have physical armor, reflected by the actual armor they are wearing; rarely, PCs can unlock talents that will grant a small amount of other armors. Creatures in the Bestiary often have innate armors of various types.
The keyword heal specifically refers to the removal of damage (not conditions). Individual effects will specify which of the three damage types to heal; by default, if not specified, the effect heals injury damage only.