howandwhy99
Adventurer
Let's say that they ignore the necromancer who wants to plumb the depths of the ancient crypt, and the guy who wants to keep it hidden.
SNIP
But what about the necromancer and the hidden crypt? What happens there? This seems to be trickier.
And what if you've got a number of "necromancers" wandering the land, with their own little plots, mucking stuff up? How many of these guys is too many? How many is too few? How does the scale of their plots (from "I want to take over my neighbour's farm" to "Let the world burn") feed into that?
You need these other guys or else the first choice (to take over the logging camp) wasn't a choice, it was the only thing for the PCs to do.
Per my original post, I would have the scenario timeline of the necromancer advance until a state of equilibrium was reached. This timeline and the state thereafter could be reentered at any future point, but will only change if the PCs actions alter the elements within the module through direct or indirect means.
A number of necromancers, foes, creatures, items, etc., do populate the land. They are parts of the other areas in the world not yet encountered or affected and therefore in equilibrium. The number of elements are based upon the size of the dungeons involved. Don't detail too much of this abstraction, only to the extent your players can reach in a single session and what you can handle. The rest can remain abstracted until events required those elements to be rolled up. If a module is added, I'd the players know. Or even let them pick one, but with the understanding it is homebrewed to fit the rules of the world. I let the players' backgrounds detail abstracted elements, working with the players on a descriptive level to incorporate them into the hidden rules behind the screen.