In The Craft, why is Nancy the only one effected by Manon? All four girls do the chant (ceremony), yet Nancy is the only one to receive the gift, at first. Sarah does at the end, but Bonnie and Rochelle never really seem to. Their magic almost seems to be coming from Nancy herself.
The other three did it as a lark, while Nancy truly wanted the power. She was the only one that really believed that it would work, out of madness or desperation. And she was the only one to be taken.
Bonnie and Rachel lost the power at the end because Sarah binded them from doing harm.