How to run a long-term deception

[Maquise]

Is there any good way to run an NPC deceiving the PCs for an extended period of time? A way that would factor in building trust, and other such things? Ideally, I'd like to run it so that while a single roll couldn't break the charade, the PCs could still have a way to see through it.

[AntiTrust]

I think some background may be needed. Do you have an idea for why this npc would be deceiving them? Without that we can really only give you generic advice.

There's no real difference between having an npc try to become the party's friend and trying to deceive them. Offer them advice or support through the npc, have the npc confide in them secrets about the npc (probably lies, but only investigation would reveal that). Humanize the npc, have him tell the party his hopes and dreams make the pc's feel comfortable around the person.

If you don't have a creature in mind I recommend the standard doppelganger, its got detect thoughts, shape change, and good bluff, and disguise skills

[Maquise]

Specifically, the npc is a heretic posing as a member of the pc's religion. They would be fluent in the ways of said religion and already ingratiated themselves with the local authority.

[Acanous]

How invested is your session on the minutae of this religeon? If you've got some basic tennents set up, with a power structure and core beliefs, you could have him confide in the PCs that sometimes, he doubts his faith, but continues on because *Insert piece of scripture here*. That way, any PC who agrees with him, he can mark out as a potential convert. Ones who disagree, have nothing to go on, so would probably just preach to him some to calm his doubts.

[Grail]

Roleplay the NPC better.

It might sound a little bit insulting, and I apologise for that if it does. But 30 years of running games has taught me many valuable lessons about this, and the best way is to roleplay it better. If the players can see through your roleplaying of the character, they won't worry what the dice do or don't say.

As to mechanically, because the game system will of course use certain skills:
If they are going to be using Sense Motive styled skills, roll them yourself, keep the results secret.

A single Sense Motive skill check shouldn't say "He is a traitor", merely that he seems nervous, or anxious, or he is acting a little bit strange. Give the guy a good Bluff though to oppose them as best as possible. If the first Sense Motive check doesn't seem to give him away, most players tend to accept that as a fait accompli that he is on the level.

You can then return to roleplaying to carry the charade.

I did this in a campaign for a long time....

Red Hand of Doom Spoiler:

When the characters came across Miha Serani, the Aranea spy, I had the group eating out of her hand, to the point that after they managed to get their hands on the Ghost Lord's phylactery, she convinced them to not to return it to him, but to take it and hide it somewhere.

She stayed with the group for about 10 or so sessions. Constantly sending information back to the Red Hand, constantly leading the characters astray.

The group ended up trusting her advice over their own instinct, as she claimed to be a scholar.

Everytime the group got into a fight, she was nowhere to be seen.

It wasn't until the group headed back to Brindol about a week before the main battle, that she left them, and by then massive damage to the good guys cause had been done. She simply disappeared into the city and it was then that they really put 1 and 1 together.

An emergency meeting with the rulers and military leaders led them to realise that they'd made a grave mistake in not taking the phylactery back. They had to try a last ditch attempt to get it back, which they did - but by the time they got back to Brindol, the battle had begun.

End result, the characters failed to save the Vale from the Horde, and it was mainly due to the duplicity of the spy.

[Asheram]

Make him helpful... a bit Too helpful. Imagine that this is a guy who's doing his best to gain the party trust and making himself needed, even if it overflows into a creepy way.

[Kol Korran]

this comes to 2 things:
- fooling the mechanics of the game. (sense motive and spells)
- fooling the players to trust the deceiver.

the first is easy- lots of ranks in bluff, and some magical item that prevents detection of alignment, lies and so on.

the second one is trickier. the idea is to play this guys as a straight up guy, as a regular guy. when you play him, don't think "ok, he is really bluffing and scheming hiding behind this persona" because most likely you'll act like it, giving away some hints of the deception.

"the best liers tell the truth the whole time... except at the crucial point". (said by someone who's name i regrettably don't remember) think of it as a decent guy and roleplay him so- it will flow more naturally, more belieavble. just keep in the back of your mind the nature of deception.

a few more things that might help:
- show that he has some interest (not necesserily the party's interest, but not ones going against them) to give this guy a purpose and place in the world. if the only options are "hey! he's SOOOO trying to be friendly" and "he's a traitorous scum" most parties will go for the second. people always suspect the friendly guy. they barely give a glance at the neutral guy.

- have the major effects happen behind scenes. the villain never shows something is wrong when surprising new happen. instead he acts as usual, and LATER use his minions/ spells/ other forms of influence to deal with things.

- have him do things that contribute in some way (according to his perceived "cause") to the players, at first very meagerly, but as trust seem to build (the PCs may seem potent) more substantially. have it be in the form of partial information, some magic items or such. the point is not to see to eager- have them belive this serves his purposes as well.

- the chinks in the deception would usually be info the enemies have that they should not know- that only allies of the party possess. how not to make it a dead give away? a few methods:

the info should be subtle, at least at first- no enemies with counter plans to the PCs moves and so on, but perhaps a well known schedule of caravans/ shipments, knowing some force is coming and being prepared, and so on. as time goes by the info should be more and more specific, gaining more and more suspicion
at first the info should be known by a fair amount of people, not easing the search. idealy, it should be info that the deceiver "shouldn't" be able to know (due to position, power and such) but got access to. the info logically could be known by other peoples, which leads us to:
"the dupe": someone the villain targets to take the fall. he plants rumors about him. perhaps plants an info piece about him in an easy mission or the like. points to you if you make the PCs actually suspect (and execute?) the wrong guy, furthering the villains' cause.


as been said above- you should play him better. don't think of playing a lier, think of playing the persona. and be a regular guy, not "Mr. Helpful".

[Maquise]

Note: I haven't actually started to play him yet, I'm still planning him. I think I have what I need now.

[docnessuno]

I don't know how much this is going to be helpful, the following is based on a character i did play and on one house rule, but i do think this can prove useful for you.
The character was a cleric of Mephistopheles posing as a cleric of a neutral god.

House rule: Each divine spell with verbal components includes the deity's name (or the name of the power the spellcaster is devoted to) in the verbal components themselves.

How it did play out:
Use spells like nondetection, misdirection to mask your alignment, undetectable/magic aura to mask compromising items.
Silent spell, memorize your spells with this feat and add your own 'made up' verbal components on top of it.
Divine focus, wear your true focus beneath your cloth/armor, possibly disguised as something else. Use a fake focus, possibly with a custom cheap enchantment to make it shed dim light for a moment on an appropriate trigger.

[Salanmander]

The tricky part to me seems to be how you play it if the players make and succeed on a sense motive check. I would recommend giving him layers of cover. For example, if he assigns them a mission to go kill a troublesome orc band (because he wants them out of the city for an afternoon while he contacts the evil overlord), he might pick one that happened to do something nasty to a friend of his. That way if they succeed on a sense motive and find out he has an ulterior motive, he can direct them to finding the _benign_ ulterior motive.

This also does make sense in-game, if you take the rules as a faithful representation of D&D reality. Presumably as a spy-type in the D&D universe he would be aware that it's possible for people to KNOW you are being less than completely honest, so he would construct layers like this to protect himself. Also, the benign ulterior motives can be extra bluffs to recover from other failed bluffs.

Lastly, look into the skill tricks from complete scoundrel.

[Fitz10019]

Deceit by proxy

Make your villain NPC with good Bluff, Malichai McVillain. Make another NPC with lousy Sense Motive, Sir Dudley Do'good. All of the party's contact is with Sir Do'good, and he honestly believes everything that McVillain has told him. Sir Do'good will never fail a Bluff check, will never set off alarms from a PC's strong Sense Motive check.

Also note, there is no Sense Motive check on written communication.

[Salanmander]

Deceit by proxy

Make your villain NPC with good Bluff, Malichai McVillain. Make another NPC with lousy Sense Motive, Sir Dudley Do'good. All of the party's contact is with Sir Do'good, and he honestly believes everything that McVillain has told him. Sir Do'good will never fail a Bluff check, will never set off alarms from a PC's strong Sense Motive check.

Also note, there is no Sense Motive check on written communication.

Do remember that OP wanted it to be possible for the PCs to figure out something was strange.

[Runeward]

I assume your PCs don't Sense Motive on every NPC they meet, so just have the NPC not do anything suspicious for a long while. Now, this won't work if you're always having the NPCs act nice and then secretly betray the PCs because the players won't trust you the GM. If that's the case... you might have to wait a while and actually introduce some honest NPCs before you can get another dishonest one to be believable.