After losing her family to a Yoma attack Priscilla decided to fight all she considered evil in the world. After joining the Organization she quickly rose to rank no2 and even then she was said to still hold more powers perhaps holding more potentional than any other Claymore before her. Like Teresa Priscilla had the ability to fight with great power even without using her Youki thus making her a dangerous opponent for anyone relying on reading the flow of Youki. Priscilla was one of the four Claymores sent to execute Teresa when she strayed from the organization but the catastrophic outcome of the battle spawned one of the most fearsome beings to ever haunt the world.