I'm in the early stages of developing an adventure, and I need some guidance.
Wealth has gone missing from a nearby mundane lord as a result of the Infernal power Wealth of Nations - a demon is interested in propping up a noble somewhere else. The now-poorer lord (or one of his advisors) has done enough accountings to believe that the loss is supernatural, and blames the closest source - the magi.
If the magi aren't particularly skilled in Quaesitorial procedure, Occult Lore, or Sense Holiness and Unholiness, what's the best way for them to figure out what's going on?
If they can find a spell trace / sigil (or equivalent) then InVi "what is this?" effects should at least reveal that the effect is non-hermetic (unless the demon is using some sort of effect disguising effect).
The best way would be, IMO, to involve the characters in the demon's schemes in some way. Have coins like the ones stolen show up at the covenant's coffers - not conclusive, since there are other sources for them, but make them rare enough for it to be suspicious. Investigation would then uncover the grog (?) who brought the coins, then the merchant that sold it to him....
Or take a more direct approach - have the demon or its servants be working for someone at the covenant, or one of their family members, or so on. Perhaps a companion will be invited to share in their uncle's windfall or celebration, or perhaps a grog starts spending money like a duke, or an iterant farmer complain about a new lord that bought the land he is on and chased him off his land.
If you want to be really blatant, have the demon act when he hears magi are called in. One way is to have him make an attempt to bargain with the PCs - say, "I'll return the money, if you guys will back off". This is a High Crime so it's a very effective source for future blackmail, so it is very unlikely to succeed but perhaps the demon figures it's worth the effort with these young magi, with the low Code of Hermes and Infernal Lore they have. Another option is for it to panic, and start sending Infernal spirits/demons against them; capturing one should allow them to make it spill on its master, although again they should be careful not to bargain with it.
Hope at least one of these will be somewhat useful,
I don't think ThePedant means the money has turned up around the covenant at all. Just that it is missing from the local noble.
As for the players, I think they are out of luck. It could be any number of people causing trouble supernaturally. Fae, demons, a hedge mage or even rival magi from another covenant. Depending on the enemies already known in the saga they would take various steps. Two option though:
Let the noble and a neutral priest interview the covenants servants and see what wealth is in the coffers. Only makes a difference if the stolen coins can be identified as not being anywhere near the covenant. However that is unlikely as both the covenant and the lord would have a decent mix of normal circulating coinage.
Call the quaesitores in. Tell them a supernatural theft is bringing trouble from the mundanes, and that they must do their jobs and investigate.
and finishing what I meant to put .... Therefore unless something is major they are unlikely to turn up on a first request.
If the covenant can somewhere monitor the treasury that is losing money then they will be able to determine a lack of Hermetic or fae influence (unless the demon is faking that). This should be enough to indicate the infernal as a possibility. If the demon is faking then I am at a loss. That's the real problem with the infernal - with Hermetic majic unable to detect it there is a real issue.
Until the magi tip their hand, why would the demon fake it? Why bother?
Remember, demons became demons first and foremost through the sin of Pride-- Why should they hide until it suits their needs? If the demon can do its work without attracting attention and not needing to simulate some other creature, then why spend the Might? Better to just trick your targets...
And I agree with the idea of attempting to pull the wizards into the mix with the offer of just "letting me go," as that is a point where the demon probably ought to try fooling the magi. It could be a very interesting situation, especially if it first tries to look like a fae, then perhaps reveals that it's possessing someone, and then perhaps shows that innocents will die (with the magi framed) if they kill it there, so that you can set up a proper showdown later....
In many cases the demon would love to see trouble come from the theft - it would just have it blamed on something other than the infernal. So the power may be trackable, but appear as either magic or fae...
Quite true, but depending on the game style, I would expect there to be several quaesitores available per tribunal. According to HOH:TL there are a total of 139 quaesitores in total, spread throughout the tribunals, so you should be able to find one.
So it is up to the quaesitor if he is too busy to find a colleague to investigate.
If one covenant accuses another of deliberately stealing from a local noble to bring mundane trouble on the first covenant, this is both the High Crime of Endangerment and of Interfering with the mundanes. So there should be no question of if the complaint is a serious crime. The only issue for me is if the magi who are having this trouble can produce enough evidence of magical involvement in the crime to require the quaesitores to involve themselves.
Either way it is a possibility for the young magi who want the crime investigated but don't have the skill themselves. Another option is asking one of their parens who is more skilled to help out.
Thanks for all the suggestions; I've been mulling things over, and these are my thoughts-
First, I'm still not sure what an InVi on the store-room would turn up. I'm assuming the demon was ignorant of (or oblivious to) the nearby covenant, as his real plot is somewhere far away; the chaos caused by removing the money from here is mostly a side effect. So there's no pretending that it's faerie action.
I'm toying with the idea that there's a hidden diabolist in the noble's house, and he's made the storeroom/treasury area into a Level 1 Infernal Aura so the demon can go about his business more easily, but I'm undecided.
Second, I think the timing will be such that, by the time that the Quaesitores or the Broken Mirror Vexillation or whoever else is the demon-fighting crew shows up after getting the message, there will be an angry nobleman at the covenant's walls, which will probably mean that calling the Quaesitores is a bad idea.
Third, I'm trying to figure out whether a highish-level demon would freak out or lay low once the magi show up. If there's a diabolist who freaks out, that might tip his hand. But otherwise, it could just be a race against the nobleman's patience.
Well, bear in mind (ambiguous or contradictory statements in a few supplements aside), Hermetic magic can detect the Infernal. What it cannot do is penetrate the lies of demons, and one of those lies may be either "no demon here" or "I'm a faerie/dragon/angel, honest" and Hermetic magic will report the lie as true. As such, Demon Detection spells are, in fact, largely useless because you can't trust them except with a positive, and even then a demon might be making someone else merely look infernally tainted. That said, by that logic Magic and Faerie detection spells are also useless as they might just reveal a demon.
That said, if the demon isn't trying to hide then InVi should detect that a demon is active, and since nothing else is dumb enough to masquerade as a demon ...
As for actually finding the demon, that's a trickier matter. Magic, aside from the first ping, is largely useless and it becomes a story matter of speaking to people and actively seeking the corrupt.
Look at the InVi guidelines for detecting spell effects...there's some in ArM5, and HoH:TL.
Basically, the magi need to go to the site of the effect (the vault that the money disapeared from). If there is currently an active effect there, it should be detectable based on its magnitude (higher magnitude = easier to detect). If there is no active effect, then there will be a residual magnitude (which is more difficult to detect) that decays depending on the original magnitude and the time since the original effect expired.
If it is non-Hermetic the magi might not get too much detail, but they may get information about what Form the effect it is closest too. If the demon is not disguising the effect, then they should also be able to determine that it is infernal. If they happen to know something about infernal magic (say, they have Infernal Lore) then they may get specific information about what the effect does/did. The more detailed information they want the higher the level of InVi spell that is needed.
Finally, it might be possible to identify something like a casting sigil in the effect (or its residual). This is handy as the magi might then be able to identify that other effects they see are produced by the same demon.
I wouldn't tell them it is a demon. At least not at the start. Make it a normal investigative adventure. Once they put 2 and 2 together you can either reveal the demon or have the demon trick them as stated repeatedly above by others (I live that, BTW ).