Advice on a spell/power adventure idea

[Richard_Chilton]

There's no real mechanic that can do what you're describing...  Other thaumaturgy (which can do anything).

When assigning a point value I'd ask these questions:
What is the range?
What is the maximum value of the attack?
Does the demon need something else (rare herbs or other components) to carry it off?
How useful is this attack?

Based on what you've said, I'd say somewhere around -2 (ritual) to -5 (thaumaturgy with 2 refinements).

But the refresh for a plot element that's attached to an NPC might need to paid for.  Does it make him a greater challenge? If not, why worry about it.  We aren't working with an XP budget or CR here - the Dresden game is a bit more free form than that.

Richard

[Richard_Chilton]

I'd recommend starting the attack at at least fair, for it to seem actually threatening
a mediocre attack, frankly, should almost never be landing a hit on anything but a mook, and probably a noncombatant one, at that
and when it comes to action of NPC vs NPC, pure narration, without any rolls whatsoever, is easier and usually better

Maybe I misunderstood, but I thought the poster wanted to start with "there's an issue" and work up to "there's a problem that you have to deal with".  A mediocre attack will probably never inflict any stress, but it will let them know that something is going on.

Richard

[Taran]

Yeah, that's the idea.  It might be easy to resist at first, but then get harder each time it happens.  My idea was to have separate mini-events described to each character prior to the start of the campaign, just to get things rolling and give them each a goal or interesting tidbit to look into.

The shapeshifter mini scene was to wake up naked in the woods with a half eaten deer beside him.  Something to say, "oh, that's not normal!"

When he first gets hit by the "attack" in-game, he'll have an idea of what might be happening, even if he resists.