If the idea is replacing the health bar for something else, perhaps this could work:
Each character has different body parts, let's say: head, chest, arms, legs, for instance.
When being attack by other characters, the damage will be seen as an injury in one of those parts. For instance, instead of 35% of damage in the health bar, "he's very bad injured in his head".
The part of the body which is affected could depend on the weapon which have been used to attack. Each type of weapon could have something like a "profile": longbows are more likely to hurt in head or chest, but not in arms or legs; whips can only hurt on chest; swords are supposed to hurt in head, arms and chest, but not legs; and so.
The same for animal's attacks. Desert snakes are supposed to attack at legs; cows and goats at chest (or better, "back"); if a falcon were implemented, it would be the king on hurting heads!
The body parts which are injured influence charrie perfomance. Hurt legs will slow your travelling pace; injured arms will difficult your gathering; hurt head will produce confusion and won't let you used machines well; A bad chest injury won't let you breath well and you will have to be outside building to have fresh air.
Character's death become when his head or his chest are injured for death. If the death injury (or the sum of lighter ones without being cured) affects legs or arms, charrie will firstly lose on of them, which be represented by losing constantly the 50% of the capability of travelling or gathering, respectely.
Wilmer B.