Working on a "social encounter" system for my ruleset, thought I'd post the condensed version here:
Primary Stats:
Resolve Points: A character or creature's resolve points represent its ability to resist persuasion. For ease of generating, a creature's resolve points equal its total hit points. Resolve points are tracked seperately from hit points.
Influence DC
The DC to "break" an opponent's resolve is equal to 15 + Will save modifier. A creature's attitude towards the target modifies the Influence DC as follows:
Animosity: +20
Hostile: +15
Unfriendly: +10
Indifferent: +5
Friendly: +0
Helpful: -5
Fanatic: -10
Resolving A Social Challenge
Basically, characters act in initiative order, "attacking" the opponent's resolve. You can use any persuasion skill you wish to attempt to influence the opponent (Diplomancy, Intimidate, Gather Information, Seduce, Torture, Bluff). If your Persuade roll beats the opponent's Influence DC, you deal 1d6 damage + Cha modifier to the opponent's resolve. For every 5 ranks you have in the persuasion skill you used, you increase the damage by +1d6.
If you wear an opponent down to 0 resolve or less, they agree to your request or are persuaded by your arguments. An opponent who has no agenda can simply choose to refuse any requests or persuasion if they reduce the opposing side to 0 hp or less.
After being defeated in a social encounter, a creature or character gains back 1/2 it's total resolve points.
If you fail to influence a creature in a social encounter, you cannot attempt to persuade it again for 24 hours.
In some encounters (especially against generic NPC crowds), you may wish to treat the entire opposing side as a single entity, rather than as individuals.
---------Fleshing out the system--------------
Everything from here on down is "advanced rules"
Modifiers to DC based on Persuasion Request
Trivial request; involves no risk, money and takes less than a minute to complete: –10
Minor request; involves no risk, little or no money and a short amount of time, usually less than 5 minutes to complete: –5
Moderate request; involves no risk, little money (up to 1 gp) and/or a moderate amount of time, usually less than an hour to complete: +0
Major request; involves some risk, money (up to 10 gp) and/or siginificant time to complete, up to 1 week +5
Serious request(1); involves risk to life or limb, lots of money (100 gp or more) and/or significant time to complete, up to 1 year: +10
Grandoise request(2); involves major risk to life or limb, large sums of money (1,000 gp or more) and/or significant time to complete, up to 10 years or more: +20
Life–altering request(3); will likely result in the demise and/or bankrupty of an individual or a lifetime dedication of time to complete: +30
1: Reduce modifier to +5 for Helpful and Fanatical targets
2: Reduce modifier to +5 for Fanatical targets and to +15 for Helpful targets
3: Reduce modifier to +10 for Fanatical targets and to +20 for Helpful targets
------------Standard Actions------------
Aid another’s Persuasion
You make a DC 10 Persuasion check. If successful, you add +2 to another being’s Persuasion check.
Avoid Confrontation
The being takes an active defense against being persuaded. It gains a +2 bonus to the Influence DC to be persuaded. This modifier lasts until the being’s next action.
Bluff
You use a lie to attempt to persuade a being to do as you ask. Make a Deception (Bluff) check against the Influence DC as normal. If you succeed, your deal 1d6 +1d6 resolve damage per 5 ranks of Deception (Bluff) you possess, plus your Charisma modifier.
Bluffing during Torture: As a special action, if you are being tortured, you can attempt to Bluff your torturer with false information. You deal damage as normal for a Bluff check. If you succeed in reducing your opponent to 0 resolve or less, you have managed to convince them that your false information is true. Until the torturer is able to otherwise ascertain that you have lied to him, he cannot attempt to torture you for the same information.
Harden Resolve
As a standard action, a creature may make a DC 15 Will save to attempt to regain resolve points. If successful, 1d6 resolves points are regained per 5 ranks of Perception (Sense Motive) the creature has.
You may only attempt to Harden Resolve once per social encounter.
Persuade
With this action, a character or creature attempts to persuade the opposing person or side to perform a task of the persuader’s choice. You can attempt to persuade up to one being per point of Charsima modifier you possess at one time.
If you make a successful Persuade attempt, you deal damage to the being’s resolve. A successful Persuade check normally deals 1d6 resolve damage + 1d6 resolve damage/5 points in the associated skill, plus your Charisma modifier.
Diplomacy: Using a form of friendly persuasion, you attempt to rally a being to your cause. You use perform to convince a creature to willingly perform a service for you. You cannot convince a creature to perform actions that oppose its basic nature or alignment.
Gather Information: You attempt to bait a being through trickery, compliments or other means to reveal information. You cannot use Persuade (Gather Information) to force a creature to reveal information that would be harmful to itself or its well–being.
Intimidate: Using strong–arm tactics or threats, you attempt to coerse a being to to do as you command. You use intimidate to force a creature to act as you command. You cannot command a creature to perform suicidal orders.
Seduce: You attempt to lure an individual through promises of favors or an emotional response to reveal information or perform a favor for you. You cannot convince a creature to willingly perform an action that would be harmful to itself or its well-being.
Torture: This skill can only be used on an opponent that cannot otherwise escape being tortured. By utilizing methods that cause physical pain to the subject, you attempt to extract information from your foe. Unlike other forms of persuasion, you can force an individual to reveal information that even it would normally not reveal due to its alignment or that may prove harmful to itself or others.
Unlike other forms of persuasion, torture deals physical damage as well as resolve damage. The amount of damage dealt is based on the implement used to torture the individual. If no implement is specificed, it is assumed the torturer is using an unarmed attack to torture the victim.
A creature being tortured can usually only respond with the Resist Torture or Bluff action.
Resist Torture
Normally, a creature being tortured can only perform this action, or respond to Torture with the Bluff action.
By resisting torture, you attempt to frustrate your opponent’s efforts to effectively torture you. You make a Will save DC 20. If you succeed, you deal 1d6 resolve damage to your torturer, plus an additional +1d6 resolve damage per +3 base Will save you have.
If you reduce the Torturer to 0 resolve, you have frustrated his attempts to extract information from you. You cannot be effectively tortured by the same opponent for 24 hours. Further torture by this individual within this time span can still inflict physical damage to you, but not resolve damage.
Sense Motive
You use Perception (Sense Motive) to attempt to determine a weak point in a being’s resolve, or to determine if you have been bluffed.
If you make a successful Perception (Sense Motive) skill check against the being’s Persuasion DC, you gain a +1 insight bonus to your Persuade checks per 5 ranks of Perception (Sense Motive) you possess.
Further if the opponent just bluffed you on his last action, you automatically regain +1d6 resolve points per 5 ranks of Perception (Sense Motive) you possess.
-----------Full Round Actions----------
Change Alignment
This is an attempt to change a being’s alignment to match your own. You cannot change a being’s alignment more than two steps in a given week. You can only attempt to change the alignment of a being who has an attitude of Friendly or better towards you.
Changing alignment is a Persuade (Seduce) check against the Influence DC. Opponents who have an alignment restriction to their class (such as Barbarians, Bards, Druids, Monks, and Paladins) gain a +10 bonus to their Influence DC if the alignment change would prevent them advancing in their class.
If you succeed, you deal damage as normal, 1d6 resolve points + 1d6 resolve points per 5 ranks of Persuade (Diplomacy), plus Charisma modifier.
If you reduce the being to 0 resolve or less, its alignment shifts one step towards yours (Law/Chaos axis first, then Good/Evil). If your opponent reduces you to 0 resolve or less, its attitude toward you degrades one grade and it retains its alignment.
Change Attitude
This is an attempt to change a being’s attitude towards the persuader to a more favorable condition. You cannot better a being’s attitutude towards you by more than two steps in a given week.
Changing attitudes is a Persuade (Diplomacy) check against the Influence DC. If you succeed, you deal damage as normal, 1d6 resolve points + 1d6 resolve points per 5 ranks of Persuade (Diplomacy), plus Charisma modifier.
If you reduce the being to 0 resolve or less, its attitude toward you improves one grade. If your opponent reduces you to 0 resolve or less, its attitude toward you degrades one grade.
Verbal Assault
This is a special form of persuasion used to attempt to overwhelm a being through non–stop talking. You make a Persuade check as normal. If you succeed, you deal an extra +1d6 resolve damage to your opponent. However, you suffer a –2 penalty to your own Resolve DC until your next turn.
You cannot use verbal assault with a Persuade (Torture) check.
-----------Free Actions----------
Capitulate to Persuasion
At any time during a social encounter, one side or the other may willingly agree to the opposing side’s attempt to Persuasion. Usually only beings whom are friendly, helpful or fanatical towards you will capitulate.
Capitulating to Torture: When a creature is reduced to ¼ of its hit points or less when tortured, it must make a Will save DC 20 to resist capitulating to the torture. A being who capitulates to Torture must truthfully answer its torturer’s questions.
-----------------FINAL NOTES---------------
The social encounter rules presented here can be used as effectively against characters as by PCs against NPCs. To a degree, that takes some of the player’s control of his character away, in that he or she can be influenced to perform actions that otherwise the player might not take – such as betraying the party or submitting to torture and revealing the party’s plan of attack against an enemy.
This is no different, however, than a combat encounter. Players don’t get to decide whether a blow hits or misses, or if it drops a foe or not (unless they use Hero Points to influence the outcome). The social encounter rules allow for the same thing – where a PC sitting at a game table munching chips might non-chalantly tell the orc warlord torturing him to buzz off or the player of the Paladin would never willingly submit to the temptations of a GM-run sultry succubus, these rules can help provide a more appropriate in-game response from the characters.
The social system still has limits – it isn’t very likely that the character in the above example would betray his party or that the Paladin would submit to the succubus, but the option does become more possible through mechanics where before it may have been likely handled purely by fiat.
Taking character action decisions out of the hands of players for non-magical reasons is almost always a bad idea. I might make an exception for torture only - but even then, you're risking the player's future affinity for his/her character, AND FOR YOUR GAME.
The minor rules benefit involved does not justify playing with or for those kinds of stakes.
I've done a PBeM where I killed a 15th level planar ranger with a succubus, and every action taken was the player's idea (once the situation became clear to the player, it was too late). It can be done. And of course, a fiend like that already has access to charm and domination powers, which can resolve within the existing game.
As this stands, it kind of looks like the "Grapple rules" version of social interaction. I'd recommend streamlining it, and excluding PCs entirely.