Diamond Nightmare Blade

8th-level / Diamond Mind

You spot a single fatal flaw in your opponent's defenses. With a single attack, you put all the force of your supreme focus into one, crippling blow.   You attempt an Intelligence (Insight) or Wisdom (Insight) check as part of this maneuver, using the target creature’s AC as the DC of the check. You then make a single melee attack against your target. If your check has succeeded the attack deals four times damage.