Originally, only one Slayer would be called at a time, activated after the previous one had died. However, there were many "Potentials" all over the world, any one of which could be chosen. Potentials lacked the true power of the Slayer, but had greater strength, coordination, agility, and speed than normal human teenagers. Potentials also experienced strange dreams of being Slayers from the past as well as having premonitions of the supernatural.