Health Points
Health Points (or HP) are a measure of a character’s very life force. Their decline could be due to all sorts of physical problems: injuries, disease, old scars, etc. Simply put, Health Points represent how much "life" the character possesses.
A creature's Size determines how many health points it has. Most characters begin the game with 30 Health Points, so long as they're about human-sized. Damage in combat lessens the character's remaining HP. When you rest, you gain back health. When health reaches zero, a character becomes unconscious. When health drops below zero, a character dies. It's curtains, ya hear? Curtains!
The Tempered Trump, which costs 1 Expoint, allows you to increase your maximum HP by 1.
For more information about how to lose or gain health, as well as the amount of HP granted to creatures of different Sizes, see Chapter 11: Life and Death.