If you activated this strike and attack an opponent, who must be flat footed or flanked, they must make a fort save or be staggered for one round. If they fail the first fortitude save they must make a secondary save based on a fortitude or will save, whichever is higher, or die. The DC for the first save is 10 + Class level + Maneuver level. The DC for the second save is 10 + half class level + Dexterity modifier. In addition, if the opponent makes any of these saves, they are immune to this maneuver from you for 24 hours.