As an action, you can make a weapon attack in an attempt to force the creature on the defensive, buying your allies critical seconds. Add the stamina die to the attack’s damage (add half if you miss by 4 or less). On a hit, the creature must succeed on a Reflex saving throw or it can’t take reactions for the duration.
A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
You can increase the damage for each additional stamina die expended.