Jeff's Combat system
Defend at all: 2 effort
Attacker wins roll, spend 4 extra effort
First Threshold: Flailing defence, Spend a large amount of wind/stamina probably somewhere in the 10-30 range
Second Threshold: failed defense minor wound, spend a large amount of wind/stamina take a small health wound
Third threshold: defense bypassed, take a bunch of health damage (and probably also stamina maybe just through carryup)
Fourth Threshold: Killing blow, take huge amount of health damage
Fatigue effects both give penalties to attack and defense (probably larger defense penalties) and shrink the threshold sizes. Thus means tired characeters are still able to defend themselves but when slip ups happen they have less reserve capability to avoid them turning into something really serious, serious wounds will start to happen, and that will probably be what takes a character out of the fight.
The goal of this system is for characters to advance but not ridiculously, in theory characters should be able to defeat roughly their level in level one characters. Because of this and the fact that everything in skillful is based on level difference in general a character will be equal to n+1 characters that are n levels lower. This system is designed for this to continue in the limit. In practice without modification high level characters will be able to beat fewer than their level due to the problem that their one shots will be overkill. These calculations assume that players have a pool of 40 and they are out of combat when this pool is exhausted
for mathematical simplicity we will assume that both sides have a wind pool of 40 for the fist calculation, this will be fixed in the second calculation
as a base a player spends 4 wind to defend an attack and 0 wind in order to make an attack for the moment this can never be reduced (it is very dangerous to reduce this as then characters become invulnerable to low level opponents) players also get bonus damage (wind expenditure by their opponent) if they beat them by enough
First assume that one player always gets a 10 and the other player rolls randomly and that a level gives a bonus of +1 to the roll we want your expected damage to double for a +1 in this case the only different potential roll result is winning by 11 thus all of the expectation needs to be in this result thus we need 4 damage on average so we need a bonus of 4*20=80 damage
clearly this is too much as that is more than killing the opponent in 1 shot, thus we will assume a level is +5 reducing the bonus damage to a manageable 16.
Next let us remove 2 of those assumptions, in this case at the same time makes it simpler first that all players have the combined hit points (instead each opponent has 40 wind but they are still dropped when it is exhausted and no fatigue) and second that they are taking a 10 on their roll. Instead both parties are now rolling a d20 and we are still getting +5 per level.
on raw d20 rolls p>= .55 p>=n+5 .3 p>=n+10 =55/400 =.1375 p>=n+15 =.0375 in this case instead the maximum random difference is 19 (a 1 and a 20) so the bonus needs to kick in at +20 if 1 level difference the damage instead needs to be 3 times as great. with a +5 the probability of getting +20 is 15/400 or about 1 in 26, thus meaning we need a bonus damage of roughly 100.