I think it's time this was better researched. I'm going to do some testing to find the actual equations for crit hit%.

__Knowns:__
- The low cap on crit% is 5%, and the high cap is 20%
- The high cap is reached at 50 more dex than the enemy's agi
- The curve is either some form of exponential, or there is a different equation for dDEX 40-50
- merits and crit weapons can break the caps.

To start off, I researched at what value of dDEX the low cap could be found. I did 1000 melee swings on level 65 lesser colibri with exactly 65 dex. I have 4/4 crit merits and I was single wielding a senju, and my number of critical hits was exactly 150, giving a crit% of 15% exactly. This means that when dDEX = 0, you are low capped on crit% rate.

My theory is that the low cap is at dDEX = 0, so when you have equal to or less dexterity than the enemy's agility, your base crit rate will be 5%. I also theorize that the equations from 0 < dDEX <= 40 and 40 < dDEX <= 50 are linear and that there are different slopes in those two integrals.

What I would like to find, and would welcome help on, is what the slopes of the dex/crit graph are in those two integrals. I'm hoping this is nice and linear, but if it turns out to be exponential it will be a bit more difficult :'-(