Similar to a Slayer-in-Training, a Slayer Potential is one of those special few who could possibly become the next Chosen One. While the Slayer-in-Training is someone who was identified and assisted in training by the Watchers Council), a Potential is able to tap into some of the abilities naturally, giving them a small taste of their possible future.
Like Slayers and Slayers-in-Training, a Potential has to be a human of female persuasion. Potentials get a +1 bonus to Kung Fu, and Getting Medieval (Neither skill can exceed 3 to start, unless this is taken in conjunction with the Slayer Quality). They also develop Fast Reaction Time.
Potentials have the Adversary (Various) Drawback, as per the Slayer-in-Training Quality.
If the character with Slayer Potential becomes the Slayer during play, she gains all the physical bonuses, but not the skill bonuses. As the Potential all ready has Fast Reaction Time, she only gains the remaining benefits the Slayer Quality offers. The new Slayer must pay 14 experience points to reach her "upgraded" status, as per the Slayer-in-Training.
Characters can have both Slayer and Slayer Potential as Qualities during character creation. Again, the skill bonuses and Fast Reaction Time do not stack. Total cost for the Combo is 18 points.
Slayer Potentials *should* not stack with Slayer-in-Training. However, a case could be made for a Potential to be located by the Council, and given proper training. If a Director should allow that, combine the two Qualities, but do not stack the Kung Fu and Getting Medieval skill bonuses. Stacking the Adversary drawback (ie increasing the capabilities of said Adversaries) is at the option of the Director. The cost for adding Slayer-in-Training later on is 3 points, 2 if you stack the Adversary Drawback. To combo them at character creation: do not stack the Kung Fu/Getting Medieval skill; Adversary is Directors option. Cost would be 7 points, 6 if stacking Adversary.
If you allow stacking Potential with Slayer-in-Training, use the following for upgrading to Slayer. During play, the character gets the attribute bonuses, but not the skill bonuses. Except for Fast Reaction Time, they gain all the other powers of the Slayer. The new Slayer must pay 11 for the upgrade, regardless of whether Adversary had been stacked.
If creating a Potential/SiT/Slayer at character creation, follow this formula: Stack all attribute bonuses, but not skills. Keep all other powers, but do not double Fast Reaction time. This combo will cost 18 points, as per the Slayer/SiT combo.