Adventures rooted in the occult detective genre straddle the line between fantasy, mystery, and horror. For the occult detective, solving paranormal mysteries is all part of the job. In these adventures, villains employ supernatural powers toward nefarious ends while characters act as detectives, interpreting events, learning patterns, deducing goals, and ultimately putting an end to the threat. investigation and cleverness take center stage in these adventures, though as in the noir stories that inspire the genre, there's plenty of room for action.
Occult detective adventures can be just as terrifying as any other horror adventures, but also might be lighter in tone. Adventurers might experience terrors only after they've happened and face a foe only once they're prepared to end its threat. Of course, there are ways to create threats distinct to this genre, such as when villains view detectives as rivals or targets.
When creating an occult detective adventure, consider what monster, magic, or other supernatural force might lend a thrilling twist to some criminal enterprise. How will the characters catch an invisible assassin or a thief that pilfers extradimensional spaces? Once the DM knows the villain's mode of operation, consider how it might give itself away. Even if the DM is not sure, listen to the characters' plans and give them opportunities to feel brilliant in the course of running adventures.
When running or creating adventures inspired by occult detective stories, consider the following questions:
What criminal or supernatural force is at large? What crime is it committing, or how is it a problem?
Who wants the villain stopped? Do they have a personal reason for this?
What evidence has the villain left behind? How is the evidence initially misleading?
What clarifying evidence will the characters discover in the course of their investigation?
How are the villain's deeds terrifying or suggestive of a larger plot? Are the characters threatened?
How might the characters trap the villain, draw them out, or predict their next move?