(Cha, Use Untrained)
Use this skill to propose a deal or negotiate with people.
Check: When you make an offer or propose a deal with an NPC, and only an NPC, you roll your Diplomacy against that subject’s Sense Motive check. If you win the check, then she accepts the deal. If you lose, she rejects the deal.
If you lose by more than 5 points, then she will detect any lies, half-truths, or deceptions that you might have used to make your deal look good, and the GM will role-play her particular reaction. If you win by more than 5 points, then she’s particularly happy with the deal in addition to not noticing any of your lies, half-truths, or deceptions.
When you negotiate with a group, you speak primarily to one subject, and the rest of the group can Aid Skill on her Sense Motive check.
GMs should be fairly liberal with situational modifiers on Diplomacy. If the subject has no reason to trust or distrust the you, then there should be no modifier. If the subject already has reason to distrust you, then anything from a +4 (the subject knows that the PC is trying to sell them something) to a +30 (the subject just watched the PC stab someone to death) might be appropriate.
When the narrative demands it, GMs should add large bonuses to the Sense Motive checks or even overrule them entirely. Villains who are currently trying their damnedest to kill, humiliate, or otherwise defeat the heroes should be very hard to fool. An entire game should never be resolved by a single Diplomacy check.
Other factors to keep in mind are risk vs. reward, on the part of the NPCs, the PC’s actions just before the attempt at Diplomacy, the PC’s appearance and presence, and the surrounding situation in which the deal takes place. A high-risk deal tends to be less attractive. It will sound fishy if a PC who just tried to kill an NPC is now ostensibly offering to help them.Alternatively, if a bunch of Big Damn Heroes walk up and ask someone to use their car to save the world, they’re more likely to say yes.
Gather Information (varies): You can also use Diplomacy to gather information about a specific topic or individual. To do this, you must spend at least 1d4 hours canvassing people at local bars, streets, or gathering places. For commonly known facts or rumours, DC 10; for obscure or secrete knowledge, DC 20 or higher. The GM is free to rule that some things are simply unknown on the street.
Action: Generally speaking, Diplomacy takes a minute or two to resolve, but GMs should be flexible. Some deals can take hours or days. You can attempt a full-round Diplomacy check in combat, but you take a -20 circumstance penalty.
Try Again: You can try again only if you alter the parameters of the deal (or at least give the impression of altering it). This is called “haggling.” You do not get a second Diplomacy roll just for offering the same deal again.