Draining shadows erupt around your foes, funneling their essence and energy into the Plane of Shadow.

Your touch deals 1d6 points of nonlethal damage per caster level (maximum 20d6) and causes the subject to become exhausted for 1 round per caster level. A Fortitude save reduces the damage by half and decreases the exhaustion to fatigue. This mystery does not stack with itself, so a creature fatigued by saving against one casting does not become exhausted by saving against a second casting.