So, I underst and you now need 195% cold mastery to max pen cold immunes but if I understand pen correctly anything below 0% is just % more damage. so like -5% is 5% increased damage.

Given that synergies also give 5% increased damage, below 0% don't syngergies still outweigh cold pen ?as they are effectively the same but cold pen only effects cold immune monsters?

it is a two-step process. synergies increase dmg, mastery lowers enemy res
total dmg = base skill dmg * (1 + bonus) * (1 - resist)

in some instances it is easy to get a lot of bonus dmg on your skills (e.g. for lightning: lightning mastery and synergies) that it is more desirable to add -enemy res from gear (e.g. griffon, crescent moon). in other instances it is easy to get a lot of -enemy res (e.g. cold mastery), that it is more desirable to add +skill dmg from gear (e.g. fathom, nightwings). thats why eschutas is not a particularly good weapon for a light sorc: the 20 percent points of increased lightning skill dmg listed on the item lead only to an actual increase of less than 2% of your dmg (assuming maxed synergies, lightning and lightning mastery on lvl40)

This post was edited by PiXi31415 on Oct 12 2022 02:27pm