Interesting question. I't s not come up in play yet for so I'm not sure. I think the issue with Probability Control isn't so much about who roll but about NPCs not having DPs.
If you are going by the book, I think the answer is the Probability Control allows NPCs to do anything the GM wants them to do.
The general guidelines for running NPCs, what it says is:
"When GM characters take actions that don't involve the heroes, the GM determines the outcome based on their capabilities; generally assume the character functions at their normal capability unless the story dictates a stroke of good or bad luck. In other words, any reasonable result the GM wants can happen."
"Remember that only the players make tests. When it comes to GM-controlled characters, you either determine the outcome of their actions based on their traits and the situation, or call for a test from the players to determine if their heroes are able to avoid or resist the effects of the other character’s action."
The implication for me is that, as written, NPCs aren't really bound by the rules and the only limiting factor is the GM's judgment.
Probability Control pushes this one step further. Probability Control essentially gives a character an special pool of DPs which can be used for Retcons or for Determined Efforts. Retcons and Determined Effort as concepts are a little fuzzy when applied from an NPC point of view. A Retcon for an NPC is basically just GMing and Determined Effort only makes sense when you are gambling on a limited number of DPs. Without this limit, Determined Effort is just another term for GM fiat.
Anyway, that's by the book.
Now if you were to keep track of the NPC's special pool of Probability Control DPs, Determined Effort could work something like this:
1. NPC attacking declares the desired margin of success (say Major).
2. Compare the static attack value of the NPC to the defensive skill of the PC + (1d6-1d6)
3. If the overall result falls short of a desired (Major) degree of success for the NPC the GM pays Determination points from the NPC's special pool Probability Control DPs to make up the difference at the rate 1 DP for each +2 required.
So essentially the PC's goal with their defence roll in this instance isn't to avoid getting hit (Determined Effort guarantees the desired result as long as you can afford it) but to try to make it as expensive for the NPC as possible.
One option which has been discussed before on this list is that whenever an NPC spends a DP against a PC, the PC gains the DP points. It isn't strictly necessary for the above example to work, but it seems to be a popular option.
Date: Sun, 9 Jan 2011 19:15:01 +0000
Subject: [icons-rpg] A villain with probability control
So, given that players are suppose to roll everything, how would you handle a villain with probability control?