Reaction rolls are very handy, but it’s not quite clear to me how they’re used in a dungeon encounter.
You make a roll for the monsters when they’re encountered, but without a CHA bonus, because nobody has had a chance to act yet.
An indifferent result is open to parley, but if the smooth-talking elf parleys, the reaction would be at +4 (for example).
Do you roll a new reaction roll once somebody talks, or just apply any bonuses to the original roll?
Something else?
This is how I do it: if it is just a monster, I just make the roll when the monster is first seen, without the CHA bonus. Then, depending on the initial reaction roll and how the PCs react, I’ll do another roll (if necessary) when parley happens, adding in the bonus to see how they react. Of course, this only works for intelligent monsters.
For NPCs: I’ll make the reaction roll with the bonus as soon as they are spotted; or, if the NPCs gain surprise, I’d make the roll and only add in any bonus if the PCs make an attempt to parley.
Works for me.
What kind of modifiers do you give, positive or negative? If the monsters are on guard duty and PCs aren’t supposed to be in that area, do you give them a higher chance to attack? Just curious because it seems unlikely that monsters really attack very often if only the positive mods are used.
I apply bonuses depending on the PCs actions, but to be honest, most of the time I either just base it on what the roll is and what the situation is, or just decide myself: for example, an armed camp of chaotic humanoids is likely to be hostile, or at least unfriendly.
Normally, I use common sense, but rely on the basic reaction rolls if I am unsure of the situation. I might use the CHA bonuses as is, or reverse them if, for example, dwarves are trying to parley with goblinoids.
Does that help?
I’d love to see what the designers have to say on this.
I personally don’t roll for reaction until AFTER the monsters are done being surprised, if the PCs surprise them. I like giving the players that choice of either getting a free round of attacks v. maybe not having to fight them.
same here - first surprise, then reaction. if the pcs parley, you can than apply the spokesman’s CHA-modifier (unless the dwarf attempts to talks äh takes down orcs first 
i make reaction rolls only if i’m not sure about monster reaction or unless their actions are pre-determined/scripted.
I use reaction rolls, unmodified by Charisma or other player-side modifiers, to determine a creature's initial disposition in pretty much all cases. (This is part of my expected clattering of dice when an encounter is nigh.) Even when their actions are easy to predict I'll use it to tell me about their disposition; a favorable result might mean that, although the orcs have orders to kill anyone they see, the last dwarves they killed had backpacks full of ale and meat, so when the PCs burst in I'll describe the orcs as reluctantly getting up from their feast and getting down to business without much zeal. On an unfavorable roll the orcs are so tensed up and pissed off that, if the party is scouting invisibly, I'll describe them as about ready to kill one another if they don't find someone else to murder pretty soon.
When players do have a positive reaction roll modifier, they'll often explicitly call for a reaction roll when they say they're talking to the monsters. As a house rule I let them roll one of the 2d6 involved; I keep the result of the other d6 secret, so they have some idea of how the parley is going but there's scope for the monster to hide the full extent of their reaction behind a poker face. If I've already made a reaction roll for this encounter, I treat it as a modifier on this second reaction roll, from -3 if the first roll was a 2 to +3 if the first roll was a 12.
I make a reaction roll for every encounter. I like the fact that even the monsters are aware that combat is freaking dangerous and usually try to avoid it if they can.
I also always apply the CHA bonus of the most charismatic PC to the initial reaction roll. My experiences with professionally charismatic people (living in L.A. and my wife working in “the Industry”) have led me to believe that charisma is actually more effective before you start talking. I give a second reaction roll that includes other modifiers (diplomacy, intimidation, ancient pacts, mystic aura, etc.) when the PCs start talking and try to use those abilities.
The official rule is:
Make a reaction roll after surprise is resolved. Add the following modifiers immediately:
Add the following modifiers only if conversation ensues:
*EXAMPLE: If an adventurer enters an NPC's house with a bloody sword in one hand and the NPC's wife's severed head in the other, impose a significant penalty on the reaction roll.
One of the things that's on my "wish list" of design mechanics is a more robust resolution method for diplomacy, intimidation, and reactions. I have a draft I've been using for ACKS Cyberpunk, but other priorities have been at the forefront of my work lately (PC, DaW, Auran Empire).
Interesting, so in the case of my players where one person has mystic aura, one has a high CHA, and a 3rd has seduction, they could potentially get a very high reaction roll after starting a conversation?
I wouldn't let different bonuses stack from different individuals. I'd instead apply the bonus of the character who takes the lead in the interaction.
EXAMPLE:
Party's reaction roll is 7.
Clarissa has CHA 13 and Seduction.
Hans has CHA 11 and Mystic Aura.
Jager has CHA 16 and Diplomacy.
The initial reaction is 7, +2 from Mystic Aura, so 9; or 7+2 from Jager's CHA, so 9.
If Jager then engages in Diplomacy, the reaction roll would go up to 11.
If Clarissa takes the lead and engages in Seduction, the reaction roll would be 7 +1 (CHA) +2 (Seduction), so 10.
If Hans takes the lead, the reaction roll would 7 +2 (Mystic Aura) 9.
Very interesting. this method has the added benefit of limiting the extent to which a reaction roll can vary. For example, I’ve had the high cha person encounter a reaction roll that I made secretly which was very bad, and he’ll try to start talking with the hope of changing the way things turn out with a new roll (he doesn’t realize it’s a new roll.) Using this method, you’re not going to see the key dynamic change a lot, but potentially getting +2 for invoking seduction or diplomacy could be JUST enough to bump up to the next reaction tier.
Your rules are all very well thought out, though they’re a bit tough on new-schoolers like me who are used to having things like this explicitly spelled out. I’m slowly learning though.
Man, we’ve got a Bard with +3 charisma. It’s really hard for me to have instantly-hostile humanoids under the RAW. (I don’t apply charisma modifiers to the reaction roll of creatures sufficiently inhuman and predatory, like Stirges.)
Could you reasonably ignore his charisma modifier for creatures he doesn’t speak the language of? I guess then you would have to house rule what qualities do and don’t transcend language.
*EXAMPLE: If an adventurer enters an NPC’s house with a bloody sword in one hand and the NPC’s wife’s severed head in the other, impose a significant penalty on the reaction roll.
Not too significant. There is a chance he’ll say, “Wow, thanks, I was going to hire someone to do that! Here’s 10 gp for your trouble!” 