A new RPG system

Let’s Talk About Damage

Just about every RPG has some sort of damage mechanic; a way of figuring out what happens when a Character takes a hit in combat.  Exactly how the Damage Mechanic is implemented is heavily tied into the underlying mechanics of the game and has an enormous impact of the “feel” of the game during play.  Here we’re going to look at some commonly used mechanics, how those tie into the underlying mechanics, and how they affect the feel of play.  Finally, we’ll introduce a possible mechanic for Living Myth.

Hit Points are a Scaling Mechanic and Pacing Mechanics

Dungeons and Dragons uses a d20 for task resolution in general, and thus as a means of determining whether or not one character hit another character.  Now let’s imagine for a moment that the entirety of combat was determines by a simple contest.  What would happen?  Well, a character with a 20 “to hit” would have a greater than 5% chance of losing combat to a character that had a 6 “to hit”. In fact, in any contest in Dungeons and Dragons a Skill 14 greater than your opponent always affords a roughly 5% chance of losing that contest.

This would cause a lot of problems for the intended design of Dungeons and Dragons, as it would make character death essentially random.  However, the central limit theorem tells us that the more times you take a measure, the more likely you are to measure its central tendency.  For example, if a contest were adjudicated by rolling 5 times, the Character with a 14 skill would have nothing to fear from the contest.

In Dungeons and Dragons Hit Points, Damage, Skill, and Armor Class all scale with the character (to varying degrees).  What this means is that as the Character levels, her capacity to outclass the lesser levels with her.  This creates a sense that the Character growth scales easily relative to the threats she is facing, yet still allows very weak opponents to have some effect on the Character.

However, Hit Points are also “dissociated” mechanics.  What I mean by this is that Hit Points (at least in D&D) are not intended to reflect the narrative happenings in play – the adjudication of what it means to lose Hit Points during play is always a struggle.  Is it a dodge? a flesh wound?  Hit Points are a complete abstraction from the narrative description of what is happening in the game, and simply present a rough guide to how much longer a particular Character can remain in combat.

Fate uses a dual mechanic called “Stress” and “Consequences”, where stress is damage ablation, and consequences reflect actual consequences of damage. Stress has a similar effect in terms of scaling as Hit Points (though less so), but are intended to provide “pacing” to combat (Hit Points do this in D&D also, again to a lesser extent).

A combat Pacing Mechanic is a means of determining how long a scene is going to go on for.  Stress is also a dissociated mechanic, in that it provides no narrative anchor, instead it just extends a scene to a statistically given length.  When it comes down to it, Stress and Hit Points are more or less the same sort of mechanic, but because Stress happens using 4dF-4dF the measurement happens in very large blocks.

Any Damage Mechanic is going to need to provide these two things at some level.  They don’t have to be dissociated, but they do need to provide scaling so that Characters aren’t dying off seemingly at random, and pacing so that combat can be more interesting than “you win”.

Consequential Mechanics

Consequential Mechanics are popular in many games.  The principle behind Consequential mechanics is that bad things should happen to those who elicit damage.  They are intended to be associate mechanics, as in the more damage you take the worse the consequence.  These are featured in Shadowrun, the World of Darkness games, and the other half of Fate.

The implementations vary, but they often run the risk of producing the “Death Spiral”.  Specifically, damage usually incurs some sort of penalty, that penalty is typically broad, and make the combatant worse at combat.  This means they are now less likely to actually hit an opponent, and thus extend the length of combat.  Systems with a death spiral can result in two combatants that are largely incapable of hitting each other if the mechanics aren’t well crafted.

The nice thing about consequential mechanics is that it’s easy to narratively anchor them.  A Game Master can describe an injury and it has a mechanical relationship that is clear to the Player.  These systems maintain the properties of Hit Points, but provide narrative anchoring and a mechanism to encourage Players to avoid damage to their characters – this damage avoidance does affect the way in which Characters engage in combat in usually narratively interesting ways, and encourage non-combat resolutions to problems.

Risk Mechanics

The last mechanic I’ll talk about is Risk based mechanics.  In a Risk based system, damage begets damage. Consider for example a d20 system where you had 10% of your current Hit Points in Damage Reduction.  This would make it so that taking 10 points of damage would reduce your Damage Reduction by 1 point.  The effect of this is that the more damage you take, the more likely you are to be killed outright.

More commonly you’d find this in systems where you have to “save” when Hit Points go below a certain level (e.g. GURPS), and this would especially hold if the difficulty is relative to the damage taken.  This sort of system provides a tactical and visceral element to play, where continuing to fight represents risk to the Character – as the fight continues and more damage is taken, the stakes are raised and the risk to reward ratio changes.  At some point the risk becomes too great and so the Player make a different choice, or they decide to continue in spite of the risk.

Also, it tends to gives a more compelling feeling to combat, because as damage is done to the enemies, the Players know that they are more likely to land a telling blow (as they are with HP systems), but because it’s stochastic, they are never certain when that will happen.

A Living Myth Damage Mechanic

In Living Myth every Character will have an Endurance attribute (think Fortitude Save), that will be represented by 0 to 10 Dice – 2 being average.  She’ll also have a combat skill using the previously described mechanic.  When she attacks he opponent and hits, she will have succeeded by a certain amount; her Degrees of Success.

So Damage will be Degree of Success + Weapon Damage vs Damage Resistance (which is Endurance + armor).  If that is a positive number, a single stress box will be checked off and for every extra 10 an additional stress box is checked off.

Here’s the kick, every time a stress box is checked off you must make an Endurance check against the number of Stress boxes you currently have.  For example, if your Endurance is 2, and you have one stress box you would roll your Endurance 2d vs the Stress 1d; in this case you’d have better than a 70% chance of success.  If you fail, you fall unconscious; if you succeed, those boxes grant Advantage (+1d) to anyone trying to attack you.

Suppose that the next hit was for 2 more stress boxes,  you would then make an Endurance check of 2d vs 3d – which you’d have roughly a 55% chance of making.  Assuming you failed you would go unconscious.

Once unconscious, you roll every round to see if you stabilize or if you are ‘bleeding’ out with the same sort of check as before.  If you succeed, you are stabilized, and are just knocked out for the scene; if you fail you take another stress box (of course someone could offer first aid to help with this check). When you have gone over 10 stress boxes, you die.

Assuming you failed the check and were knocked out, what is the chance of dying without any aid?  It’s another check against a 3, times a check against a 4, times a check against a 5, etc… which works out to .5555*.6299*.6856*.7297*.7643*.7934*.83*.92 which come out to around an 8% chance of dying after 8 rounds.  If you resisted Knock Out for longer, you would find the odds of dying after the knock out to be increased and take less time; so whenever damage is taken the Player experiences an escalating risk factor – but death is never presented as an instantaneous risk.


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