The first confessor was created in an experiment. Since then all confessors born had the power to control someone with their power, making them completly lose their free will. The person confessed, no matter what, always wanted to please their mistress. Even the most hardened and vile criminals would confess their crimes if the Confessor so wishs. If she wanted him to die on the spot, he would simply drop dead. Pleasing their mistress is all that matters to them.