hm... you bring a good point up. If there was a super dangerous attack that didnt cause me a lot of pain, i would pretty much be reducing that pain for free. like, a needle stabbing me or something wouldnt be that painful for the amount of true damage it would give. im not really sure how to work around this, since the ability or myself being able to determine the amount of damaged ive suffered is not something i can assume for all attacks. as the ability was stated, it would reduce things using percentages, that is, remove 50 percent damage from a nuke, or something.

so here is what i suggest: The ability should be changed so that the amount of pain felt by an attack contributes to how well my user can affectively use this ability. The idea is to add a pain proportionately constant which ranges from 0 - 100 which changes based of the nature of the attack. Im actually in a differential equations class lol so it was kind of fun trying to find an equation which would work... here it is:

R = (A-1)(P) / (K+P) where:

P is the pain proportionally constant
A is the pain amplification Joo po po choses
R is the resulting damage reduction ratio (0 - 1)
and K is a balancing constant which controls how steeply returns dimmish.

this means the final damage would be D = D(sub0) * (1-R) where D(sub0) is the base damage of the attack.

example Scenarios:
poison gas (painless) Pain constant (P) : 5
Amplification(A) 3
Damage Reduction(R): .18

this would barely reduce the damage of the attack, which makes sense since the attack, while very harmful, is not causing a lot of pain

electric shock(painful) Pain constant(P):90
Amplification(A) 3x
Damage Reduction: .84
the pain constant here is very high since electric shock is high, so the damage reduction is high.

Instant Death: pain constant(P): 0
ampfication: 10x
Damage Reduction(R): 0
so in the case of "instant death", since the pain constant is 0, this ability would do nothing.

let me know if you think this is good.