Limit Breaker

You are able to channel the pain you take into anger, which you can then use to deliver a powerful strike once you endure enough and your anger breaks its limit.

You have a new stat called "Limit Points". Each point of damage you take gives you one limit point. Healing does nothing to these limit points, and you keep them from battle to battle. You also keep them if you drop to 0 hit points.

Once you collect a number of limit points equal to your level * 20, you can use your limit breaker. This is a strike fueled by your anger, and may be a series of blows, a deadly accurate strike, or a dangerously powerful strike. Whatever form it takes, the next time you make an attack with an unarmed strike or a weapon, you double the damage dice for it. For example, if you do it with a shortsword, the damage is 2d6 instead of 1d6. This ability stacks with critical hits. Using your limit breaker resets your limit points to 0.

(in case you're wondering, yes, this is a FFVII reference.)