Thursday, April 14, 2011

Abstracting Hit Points (for Pathfinder)

Ok, I probably should know better than intrude upon this subject, but… I just can’t resist.

Today it’s already common knowledge that Hit Points should represent an abstract mechanic instead of reflecting real physical status of a character. That’s why official D&D/Pathfinder rules generally don’t care about any type of Death Spiral rule. Either you’re in, fighting, or you’re out, not fighting. Beyond this simple assumption, anything else is (or should had been) left to the hands of the Gamemaster.

It’s easy to keep this mentality with the Original Edition and its subsequent games (like many retro-clones of today). The problem is with later editions, where the idea of “Hit Points mean Physical Vitality” are so strong that many d20 variants actually create subsystems to deal directly with this (like the famous Vitality/Wounds system from the first Star Wars d20). We also have the additional complication that the official healing rules reinforce Hit Points’ recovery as wounds treatment. Ironically, the so criticized 4th Edition of D&D actually helped in this regard with its Healing Surge rule.

So, what I’m proposing to do here is: I’m going to take the Hit Points rule and really try to use it as an abstract mechanic. Hit Points now represent only your capacity to keep fighting. Nothing else. They don’t mean vigor, wounds, physical vitality etc.

How am I going to do this? I don’t have a clue so, please, just bear with me (and forgive my lack of practice with English).

Hit Points Revision

First rule: Hit Points are your fighting durability, just that. Out of combat, they don’t come into the game. During combat, when your HPs hit 0, you’re out of battle. That could signify that your character is unconscious, bleeding or just knocked down. Because of that, HPs don’t go below 0.

Whenever your character’s HPs hit 0, further damage goes to Constitution (i.e. you’re really wounded). If you suffer such damage, make a Constitution check DC 15. Failure means you’re down. Failure by 5+ means you’re bleeding and have 25% of suffering 1 point of Con damage each round (75% per minute). A success by a margin of 5 or more means you can keep fighting, but you’re staggered, fatigued and – most important – any damage you suffer goes right to your Constitution (Undead and Construct suffer Strength damage).

As you can see, your Constitution dictates your physical health.  If you’re an Undead or Construct, your Strength determines your physical resistance (you could even house-rule this and let these creatures use their Str modifier to Fortitude checks against attacks like disintegrate).

After any combat encounter, all characters involved are restored to half their full HPs (if below) after a short minute of rest. They also recover their character level (and Ability Score modifier) automatically after each hour (resting or not). If they rest completely for one full hour, they recover all their HPs.

Since Hit Points have nothing to do with vitality anymore, we’re going to use a new rule to determine a character’s HPs total. Hit Dice stay the same, the difference is the Ability Score modifier used. Instead of Constitution, use the main Ability Score of your class. Yes, this is a little radical, but think about it: HPs represent the capacity to stand against your enemies in a fight. In a battle, a Fighter will use his Strength to better block and withstand blows; a Wizard his higher Intelligence to change his stance and pick a better position to defend himself; a Rogue will use his Dexterity to evade in the last instant an otherwise fatal blow etc. Remember: it’s an abstraction of your fighting capacity.

Alchemists, Summoners, Witches and Wizards use Intelligence; Barbarians use Strength or Constitution (choose one at 1st class level); Bards, Oracles and Sorcerer use Charisma; Cavaliers, Fighter, Paladins (Anti-Paladins) and Samurai use Strength; Clerics, Druids, Monks and Ninja use Wisdom; Gunslingers and Rogues use Dexterity; Magus use Strength or Intelligence (choose one at 1st class level); Rangers use Strength or Wisdom (choose one at 1st class level) – these are just my personal guidelines, use the Ability Scores that better suit you.

An important rule: damage to Ability Scores has no consequence to Hit Points. Don’t readjust your HPs total if your suffer damage to your main Ability Score.

One intentional consequence of this rule is that player characters will have more HPs, which is good for the traditional heroic feel of Pathfinder. Actually, with HPs been now an abstract mechanic, it becomes easier for the Gamemaster to adjust the game to his liking. Do you want a horror-style game? Just remove any Ability Score modifier from the character’s HPs total.

Nonlethal damage would work normally under this rule and are fully recovered after one minute of rest. Due to the new nature of Hit Points, I suggest removing the -4 penalty for delivering nonlethal damage. It becomes a matter of choice rather than a tactical option. In fact, you can simply remove nonlethal damage altogether from Pathfinder. Each time a character attacks he can opt to make a “nonlethal attack”, if it deals more damage than the target’s Hit Points, he doesn’t suffer Constitution damage.

Another rule: coup de graces. These attacks do damage directly to Constitution. Now, an important observation: if a target is completely defenseless (not necessarily unconscious), they also suffer damage directly to Constitution. This include things like a hidden orc archer in the woods (the classic example that started the so-called “sniper rule”, from the Forge of Fury module, back in the days of D&D 3.0).

How about monsters? My suggestion is to keep using them (and NPCs) as written. They’re already balanced to the game’s CR system and work just fine with this new perspective. But, if you insist, you could try to readjust monsters’ HP total by picking a new Ability Score modifier based on its type (Giants could keep using Con; Aberrations could use Int; etc).

Finally, an aesthetic but necessary change: all “Cure” spells are now renamed to “Battle Reinvigoration”. “Cure Light Wounds” would now be called “Battle Reinvigoration I” (Ok, the name isn’t good; this is just a suggestion to better reflect the new mechanic).

Variant Rule: Channeling Energy and Bard Music
You may note that with these rules the Channel Energy class trait doesn’t make a lot of sense anymore. You could argue that positive energy boost a creature’s “resistance and will to fight”, but I prefer to change the rule.
Channel Energy now only deal damage or “reinvigorate” Undeads – its more easy for me to explain how an evil priest can increase Undeads’ vigor during a fight with negative energy. To compensate for this loss, you can give to positive-channeling Clerics either Turning Undead or Alignment Channel as bonus feats. Another option is to let these Clerics use their Channel energy to heal Constitution damage (each dice of Channel Energy heals 1 point of Con damage).
And the Bard? Now that HPs are an abstract stat, it’s reasonable to assume that bard music can “encourage and inspire” allies during battle (i.e. recover HPs). Actually, I was always a fan of this approach (even with the traditional HPs rule). When the Bard uses Inspire Courage he also lets each ally recovers a number of HPs equal to 1d4 per round of performance. This bonus increases at every four levels the Bard has attained beyond 3rd (to a maximum of 6d4 at 19th level).

Variant Rule: Lethal Critical Hits
Every critical hit requires a Fort save (DC 10 + ½ the AC hit by the attacker). Failure means the target also suffer Con damage equal to the weapon dice plus its critical multiplier, minus 1. For example: a longsword (1d8 damage, x2) would deal 1d8+1 Con damage; a battleaxe (1d12, x3) would deal 1d12+2 Con damage.

Variant Rule: Catching your Breath
Once per day, you can spend a standard action (that doesn’t provoke an attack of opportunity) to recover 25% of your hit points.
Fighters can catch their breaths more often per day. They can do it a second time at 6th level, a third at 11th level and a fourth at 15th level.
As a variant of a variant, the Gamemaster can allow all classes to gain extra “breaths” per day. Just give them an additional “breath” for every extra attack they gained through BAB advancement.

Variant Rule: Saving Against Coups de grace
If you think the coup de grace rule is too brutal (and it is), you can allow defenseless targets a Fortitude saving throw (DC 15 + Con damage) to reduce any damage by half.

Variant Rule: Life Points, Body Points, Vitality, Vigor, Wounds etc.
This goes a little against the point of these rules, but if you think that characters should get more resilient when leveling up create a new stat called Life Points (or another similar name). Your Life Points represent actual injuries to your body sustained through battle. You can support a number of Life Points equal to your Constitution + your character level.
If you lose even one Life Point you are instantly staggered and fatigued. You also must roll a Con check to stop bleeding. If you’re out of HPs you risk going down and out of battle normally. If you’re defenseless, all damage goes to Life Points.
Your Life Points recover like normal ability damage. If you suffer Con damage, you lose an equal number of Life Points. If either your Life Points or Constitution reaches 0, you’re dead.
Again, you can modulate this rule to better adapt the game to your needs. Another option is that Life Points equal your Constitution + ½ your character level or – my favorite – Constitution + your BAB.
This rule is very reminiscent to the old Vitality/Wound system to my liking, but may enjoy it.

Variant Rule: Playing with Nonlethal Damage
Here are two other options to implement nonlethal damage as seen in Pathfinder. Both rules require a new stat called Bloodied. This means the thing as in D&D 4th Edition: half of your maximum HPs. If you suffer more nonlethal damage than your current HPs or your Bloodied stat (whichever is lower) you’re either staggered or removed from battle automatically (no Constitution check to keep fighting).
The second option lends a lot more strength to the nonlethal damage rule. The first option gives a little tactical advantage; if you’re using the first option remember that the target is automatically removed from battle once his nonlethal damage reaches his current HPs.

Environmental Damage

A particular consequence of the new Hit Points rule is that they no longer reflect general resiliency or vitality. This is done by the Constitution Ability Score. Fire, acid, poison, asphyxiation, deprivation and types of environmental damage now go to Constitution.

A little perspective is important to implement this rule. An example: if an enemy is using a lit torch against you, you lose HPs normally (the fire damage doesn’t go to Con). The same holds true to a wizard casting fireballs – these spells are meant for battle and should be interpreted in a cinematic way (if you don’t agree with this, then you really should search for a different variant system, like the classic Grim’n’Gritty).

Now, if a character is thrown in a giant sacrificial pit, he should suffer damage directly to his Con (from the burning embers at the deep of the pit and from the fall). The pit is not part of the combat, but a scene trapping (and thus environmental damage).

An exception to the statement above is that using poison or acid (not an acid magic weapon!) always deal Constitution damage. This is a design decision done to reinforce these genre tropes: acid and poison are usually stupidly dangerous in fantasy novel and myths.

Below I suggest some Constitution damage values caused by environmental damage. These tables were based on Runequest (actually Mongoose’s Runequest II) and should be used just as guidelines. When creating new environmental damage values, try to remember that in D&D a normal human has a Constitution of 10-11.

Acid Damage per Round: 1d2 (weak)/1d4 (medium)/1d6 (strong)

Distance Fallen Damage Taken
4 feet or less         no damage
5-15 feet                1D4
15-30 feet              2D4
31-45 feet              3D4
46-60feet               4D4
+15 feet +1D4 (maximum 10d4)
Note: Water let you ignore the first damage dice.
Variant: A character can attempt a For save for half damage, DC 15 + Con damage.

Fire and Heat
Damage                 Source Example                                                     Damage*
Small Fire              Camp fire, cooking fire                                               1D6 points
Large Fire              Scolding steam, large bonfires, burning rooms             2D6 points
Inferno                  Lava, inside a blast furnace                                          3D6 points
*I recommend fire damage to be dealt not every round, but once per minute (or every three rounds, Gamemaster’s call).

Cold, Heat, Starvation, Thirsty…
I’m gonna be honest here: I rarely keep track of these rules and use them more for dramatic purposes. So, instead of elaborating different tables, I’m providing a simple progression (from the acid rules): 1d2/1d4/1d6. Use these to simulate these conditions, adjusting the time period to the particular circumstances.
For example, the official Pathfinder rules state that a character can survive without water 1 day plus his Constitution score in hours. After this period I would deal 1d6 damage every 12 hours (or 1d6 per hour in a hot desert). Likewise, after 3 days without food I would deal 1d2 damage per day to the character. If he’s exerting himself I would increase this to 1d4.
Heat and cold can easily be simulated with this philosophy.
I recommend detailing damage caused by these factors, to better recover them if the character finds some shelter or food (instead of using the traditional 1 point of Constitution per day).

The Easy Way

You think the rules above are a lot of crap? (They probably are…) If you do, I thought about a second and easier option to reflect Hit Points’ abstract nature. Just use the Reserve Points rule from Unearthed Arcana together with the design philosophy behind Trailblazer’s rest rules (I recommend that for every one hour of rest, all characters recover 50% of their Reserve Points).