From: tao@fine.princeton.edu (Terry Tao)
Subject: Re: Hit Points and increasing levels
Organization: Princeton University
Date: Fri, 9 Oct 1992 20:19:19 GMT

OK, having listened to some new hp variations, I now offer a tentative
"new" system.

There are two kinds of hit points: physical hp and pain hp.  Physical hp
are hit points that really hurt.  Broken arms, etc.  Pain hp are mere flesh
wounds in comparison.

A first level character still has the same number of hp, but 1 of them is
physical, as well as any constitution bonus.  Example: Cleric with 1d8 hp
and 16 constitution (+2) rolls 5 on the dice.  He thus has 7 hp: 1+2 = 3 of
them physical, the rest (4) pain.

For each level gained, all the hp gained goes to pain.  On second level,
the Cleric gets another 1d8+2 pain hp.

However! physical hp do grow slightly.  Each time a player's base Thac0
goes down due to level, physical hp increase by 1.  Hence, fighters get
another 1 physical hp per level, clerics 2 per three levels (I think..) and
so on.  This gives PC's slightly more hp then they really deserve, but the
penalties below balance that.  Under no circumstances can physical hp
exceed Constitution: if they ever do, the excess is converted to pain hp.

Monsters get 1 physical hp per HD, and also any bonuses to the roll are
physical.  Hence a monster with 2+3 HD has 5 physical hp and 2d8 pain hp.
Note monsters have slightly more hp than usual.  A goblin with 1-1 HD has 1
physical hp and 1d8 - 1 pain hp (minimum 1): penalties are not subtracted
from physical hp.

Large creatures get double physical hp, giant creatures quadruple, and huge
creatures octuple.  This represents the sheer thickness of the vital organs
due to massive size.  The limit that physical hp are less than or equal to
Con is also doubled, etc.  Small creatures and Tiny creatures have half
normal physical hp, but small PCs can still have as many hp as
Constitution, eventually.  (This allows really small creatures to be
*squashed*.)

Damage by weapons, fire, etc is usually taken from the pain hit points
first.  However, if a natural 20 is rolled (and 20 is not the only number
that can hit) or a sucessfull backstab is made, the hit may be critical.  The attacker
gets another hit roll, with the following modifiers:

+1 for every fighter level or HD of the attacker
+1 for every thief level of the attacker (backstab only: supercedes
previous modifier) 
-1 for every fighter level or HD of the defender (if he is aware of
the danger!) 
-1 if metal armor is worn (reinforces the AC bonus of the armor)
+1 if a piercing weapon is used
-1 if a bludgeoning weapon is used


(a fighter level is defined to be the difference between 21 and the base
Thac0 from level alone.  Hence two thief levels equals a fighter level.
Only thiefs - not even bards - get the backstab bonus.  Well, of course,
thats because bards can't backstab.)

If the roll misses, then normal damage is done only.  If the roll hits,
subtract the number rolled from the largest number that misses, halve this
and round up: and take
that as phyiscal damage in addition to the normal pain damage.  (It is quite
possible for the physical damage to exceed the normal pain damage, e.g. a
dagger scoring critically may inflict 1d4 pain and 5 physical on a lucky
critical hit).
 
If the roll is a natural 20, ALL the damage is physical damage - quite
dangerous considering how few physical hp one gets.  If the roll is not a
natural 20 but is a modified 20 or higher, then normal damage is inflicted
and the roll is made again, but with a cumulative -1 penalty.  a natural 1
will always fail to critical.

Example: A 4th level fighter swings a longsword at a 4+1 HD ogre.  He rolls
a natural 20.  Now he is assured of at least inflicting normal damage.  The
next roll is to see if he criticals.  The ogre is wearing only leather
armor, and the modifiers are +4 - 4, i.e. no modifier.  The fighter hits
again with an 18.  This is better than the 8 he needed to hit, so he scores
(18-7)/2 = 6 hp of physical damage and 1d8 + 1 = 6 of normal damage (he has 16
strength).  Now the ogre has (4+1)*2 = 10 physical hp and 4d8 = 20 pain hp.
After this hit he has 4hp physical and 14 hp pain.  

Physical point loss is dangerous, each one lost has one of the following
effects:

roll 1d? 

1 lose initiative next round
2 -1 to hit until healed
3 +2 to initiative until healed
4 -1' to movement rate until healed
5 -1 to random attribute until healed

etc.  I haven't worked out this part yet fully, but you get the idea.
There are lots of gory critical hit tables for inspiration anyway.  If you
lose all your pain hp but you have at least 50% of your physical hp then
you are too exhausted to fight (lose Dex bonuses to AC etc) or cast spells,
etc, but you are still awake and can walk slowly with at most light
encumberance.  If you have no pain hp but 50% of your physical or less then
you fall unconscious for as many rounds as the difference between 50% of
max physical hp and your current physical hp, then you wake up with 1 pain
hp.  If you have 0 physical or less then you are dying fast: each round you
lose 1d6 pain points and one physical point: -10 physical points and you're
dead, 0 pain points and negative physical points and you are in a
coma (note you can never get negative pain, it's transferred into the
physical.).  Note that 15th level fighters who still have 50 pain hp but were
floored by a lucky arrow shot in the heart will stay awakw the longest with
this scenario: this makes for some good heroic final words, etc.  If the
wounds are tended to expertly the physical hp recover up to 1, as does the
pain hp, using the Death's door's rules.

Healing: natural healing heals 1 physical hp per day, and as many pain hp
per day as fighter levels, or HD.  Hence a 5th level cleric, having   thaco
of 18 and thus having 3 fighter levels, gains 1 physical hp and 4 pain hp
per day.  Excess hp gained in one category can be transferred into the other category, e.g. a 10th level fighter with top physical hp but still wounded by
20 pain hp can gain 11 pain hp a day.  The whole week of rest allows the
physical hp to heal by the amount of the constitution bonus (if positive),
and pain hp to increase by the constitution score.  Cure wounds etc tends
physical hp first at normal rates, but for pain hp the curative points are
multiplied by a factor of (fighter level / 4), rounded upwards.  Thus a
person who is a 10th level fighter, wounded for 2 physical hp and 20 pain
hp, recieves a cure light wounds.  the 1d8 roll is made and found to be 7.
The first 2 of the 7 points cure the physical side, and the other five are
tripled to give 15 curative points for the pain hp.  The end result is that
the 10th level fighter is now down only 5 pain hp.

As soon as each physical hp is healed its debilitative effect goes away.  A
priority system for decideding which goes first may be needed (I haven't
got all the details yet).

Another thing to work out is the effect of non-weapon attacks, or attacks
when the defender is helpless.  One thing: the "backstab" multiplier for
damage is now negated.  The reason? note that the modifiers for the
backstab hit are now greatly in favor of the stabbing thief, considering
that the counterweighting  effect of the defender's fighter levels are
gone.  There is a good chance for a high level thief to keep rolling above
20 for a while and cause double, triple, etc damage with some criticals
thrown in.  (Sideline: one may rule that a thief can attempt to hit a
backstab while the attacker is aware of the thief: now the thief suffers a
-4 
AC penalty, and has to make a normal hit roll at no bonus to achieve the
backstab, and the defender's adjustments apply in the critical hit roll.)

Final note: aid spells and similar contrivances add to pain hp only.

Any comments? as you can see, this is still a prototype system.  I've yet
to test it yet, but it is the sort of thing you need to do to accomodate
all the objections listed in previous nets

Terry.
Organization: Junior, Mathematics, Carnegie Mellon, Pittsburgh, PA