This is a question about a crossover game that uses the 20th anniversary rules for Mage and Vampire so ideally I'd like a 20th anniversary answer.
I had an odd situation in the last session where a vampire with Dominate used their Command power on a Mage that had an active Mind 1 'mental shield' effect.
I ruled that the Mage was allowed to make an Arete roll and deduct the successes from the Dominate effect but I suspect that this was not a balanced call as the relative sizes of the dice pools are markedly different even though the difficulties are also different.
- Vampire's dice pool is Manipulation + Intimidation vs current Willpower
- Mage's dice pool is Arete vs 3 or 4
If this were Mage vs Mage it would be:
- Mage's Mind 4 mind control effect using Arete vs Willpower +3
- Mage's Mind 1 mental shield effect using Arete vs 3 or 4
Is there a better way to handle this in the future where the Dominate Discipline comes into conflict with the Mind Sphere?
Both answers so far are really good and I've voted them up but I'm going to go with something closest to Flux's answer for my specific situation although I think Doctor Kill's answer would be better in general.
I'm going to add the successes from the Arete roll for the Mental Shield to the Mage's current Willpower when setting the difficulty for the Manipulation + Intimidation roll.
Dominate and Mental Shield are both 1 dot effects/powers so they should be able to oppose each other reasonably well but I feel that the mental shield effect should not be an opposed roll like an attack vs a dodge but a difficulty increase like trying to pick a lock in the dark when it's raining.