Over the years I have seen a few write-ups done for "fortuneteller" NPCs. This is my take, and yes it is based on the d20 magic 8-ball model.
First, the DM assigns an accuracy rating for the NPC. For this example I am using a d8 as my basis, which translates into 12.5% accuracy for each level of accuracy assigned to the fortuneteller.
Madam Dubrova has an accuracy of 3 in 8 (37.5%) for each question being answered correctly.
The following is a simple d20 table of typical answers to yes/no questions. 10 are positive, 5 are non-committal, and 5 are negative. The reasoning for this is simple.. people prefer positive answers to their questions and a fortuneteller is above all a business woman.
|Right Click and Save, to download table.|
As a rule of thumb, a fortuneteller can expect to command a price of 50 coins per level of accuracy assigned to them. I say coins because it is up to the DM whether to charge copper, silver, or gold. Fortunetellers are a shrewd lot and charge each customer according to their ability to pay. This also gives players a reason to go out scrambling for money to pay the fortuneteller for her services.
For our example, Madam Dubrova can be expected to charge 150 gold coins for answering each question.. as players will often have access to gold.
To make things even more interesting, Madam Dubrova isn't just a psychic, she deals in real information. Using a network of informants, from her cat Familiar, to clients who owe her debts (and happen to work for important people), she has a wealth of insider knowledge at her command. She will often drop these tidbits into her sessions to boost the "accuracy" of her predictions, and gain the confidence of her "customers".
A few levels of spellcaster (usually cleric or druid) can also help round out a fortunetelling NPC.
|The image for Madame Dubrova is derived from the Public Domain |
"A Study, No. 1 / Rudolph Eickemeyer / 1901"