The way my system has been progressing, there are three aspects to a character that are most important, and influence everything that character does. Those three things are the character's Endurance Points, Ability Scores, and Action points.
Endurance points, EP for short, represent a character's health and energy. EP can be drained through combat - bruises, cuts, scrapes, and other superficial wounds are tracked with EP. EP can also be drained by actions of heavy exertion - adding extra damage to an attack, sprinting, or traveling long distances without a break will all drain EP as well. When a character's EP is 0 or below, that character falls unconscious - unable to move and at the mercy of his or her enemies.
Ability scores have been touched on in the last two posts, but I'll go over them here in more depth. There are eight ability scores, and each ability score has its own set of skills that it governs. Four of the ability scores are physical: Strength, Agility, Finesse and Vitality. The other four ability scores are mental: Perception, Willpower, Intelligence and Charm. Each ability score can range from 1 to 6, and 3 is the average ability for a healthy adult human in all areas.
Some skills are hybrid and depend on multiple ability scores - in cases like these, they use whichever of the ability scores is lowest.
Ability scores do more than just tell characters how well they do at using their skills, however. For instance, many actions in combat such as movement depend on agility without it being related to a skill. Strength also helps determine how much equipment a character can carry before being impaired by the weight.
Most importantly, ability scores keep track of critical damage to a character's body and mind. Occasionally, an attack on a character will be a critical hit, and it will do damage to one of that character's ability scores alongside EP damage. Representing sprained ankles, broken bones, torn muscles and profound blood loss, ability score damage is harder to heal than damage to EP, and most importantly, when a character's vitality has been reduced to 0, that character is dead.
Fear not however! Armor, while not making it more difficult to hit a character, does absorb damage dealt by critical blows and normal attacks alike, so your ability scores will be safe if you wear the proper protection.
Finally, action points will be gone over in more depth in the next post, but action points are my system's answer to "How do you make turn based combat represent everything going on at once?" All characters have a limited amount of them, and they regenerate every turn. All actions done in combat require action points, and the more time the action takes, the more action points it uses.
A character with more action points than his opponent will have a significant advantage in combat, because he will literally be able to perform more actions. Not only that, but characters need to conserve action points, because they're also used to defend against attacks. If you never make defensive actions, your character will probably die very quickly, so it's important to balance out how many action points you use for offense, and how many you use for defense.
Action points are also used to interrupt other characters' turns, and make your own actions before they have a chance to finish theirs. This is the aspect of action points I like the most, and I'm greatly looking forward to describing it in the next post.