In every edition it has baffled new players: “If a first-level character can take two or three sword hits, what does it mean when a high-level character can take ten or fifty? Can the 20th-level fighter really survive being stabbed that many times?” The confusion between hit points and physical injury led many groups to adopt the nifty wounds and vitality system, which fell out of favour when it was discovered that the increasingly lethal critical hits gave every character a 50% of being killed outright by a stray bolt before level 20.
The following article should help you to add a narrative explanation to the cold abstraction of the hit points system, including its results: damage, healing, temporary HP, and those fourth edition specifics, healing surges and minions.
Hit points are a figure that can represent anything that prevents a character or creature from being seriously injured by an otherwise successful attack. HP doesn’t always measure physical wounds, but rather can represent stamina, morale, easily treated minor wounds, and even abstract things like luck or divine protection. Hit points are like wealth: where you get it isn’t as important as the total purchasing power you have access to.
Examples: Gorlarg the Fighter takes a punch in the jaw, but Gorlarg’s tough enough that he doesn’t even flinch. Gil-Lachel the sorcerer is protected by an array of subtle magical enchantments. Lothar the cleric praises Sehanine when the dwarf swinging an axe at his head makes an unlikely fumble. Ansen the Swift counts his blessings when a flock of arrows heading his way all miss their mark.
Hit point damage
Hit point damage has two defining properties. First, it is cumulative: unlike a missed attack, each amount of hit point damage brings you slightly closer to certain peril. Second, it imposes no immediate penalty, until enough damage is accumulated that the character is mortally wounded, killed, or knocked unconscious. This means that only the last attack represents a serious debilitating injury, while the rest represent something less significant: a painful hit, a series of strikes that wears down the opponent’s stamina.
Monsters don’t always follow the same restrictions as humanoid characters. A skeleton might be able to lose half of its ribcage without penalty to combat, while a regenerating creature like a troll can suffer severed limbs without much bother.
Examples: Gorlarg stoically absorbs another hit from the ogre’s club, but his will to fight is fading with every strike. An undead spirit feels its corporeal strength fade as it’s struck with burning arcane magic.
Healing canonically counters damage by healing wounds, but if we’re to be realistic then the first few hit points you lose are barely wounds at all. It’s safe to say that healing simply restores whatever vitality is lost in combat. Healing is at its most dramatic when it saves a hero from a mortal wound, but the effect is more subtle when the same healing spell or duration of rest restores stamina or spirit.
Temporary hit points
Temporary hit points are usually from a magical effect or morale boosting effect. In that sense they’re similar to normal hit points, except extra.
Healing surges (4th edition)
A common misconception is that healing surges turn every fourth edition character into a cleric who can heal by themself in combat. A more accurate assessment is that healing surges are a daily limit to how much of your hit points (stamina, morale, and so on) you can recover out of combat or when healed with magic. Your mind and body can only take so much punishment before taking a rest, even when healing spells are applied.
After a battle, you can bandage minor injuries and rest briefly to regain your stamina and courage.
Minions (4th Edition)
An oddity of 4E, minions are D&D creatures who in effect have only one hit point, because they always go down in one successful hit. They fill a useful mechanical role, but how do they fit in a world where monsters take multiple hits?
The solution is this: Minions have no hit points. The rank and file creatures, the peasants of that monster’s race, minions simply have none of the features required to give them hit points: no combat toughness, stern morale, magical defences or luck of any sort. You either hit their AC or you don’t, and if you do, because you’re an adventurer and not a chump, you’re quite certain to deliver at least a knockout blow.