Characters go unconcious when they reach 0 mortal points. If they have -10 mortal points or above, the points heal back at 1 an hour.
Anything less than -10 and characters lose 1 mortal point per round. If they reach the negative of their normal max, they are dead. This means that adventuring types with a few levels are harder to kill both on the plus side and the minus side of 0. They just don't like to lose and their bodies and minds fight to stay alive even while severely injured.
First aid skill adds it's skill points to the mortal points of a character and stops the negative modifier for those under -10. This can only be used once per battle per person injured in that battle.
Any healing spell adds it's points to the mortal point total and stops the negative modifier also. All healing spells have different effects based on the character. Some characters are better at healing than others.
If after magical healing or first aid, the character still isn't above -10, then the character will need a doctor in order to heal.