Not sure at all what's going on here with bone break, but I learned recently that cursed amp always works at 100% effectiveness vs immunes, regardless of sunder or not. I confirmed this by finding a stone skin game, and having bound demon proc amp on wraith which should have 150% resist (without bone break at any point).
The text underneath no longer shows phys immune. I sanity checked with another character using amp from brand bow, and this did not break the immunity.
Hmm I think its possible wraiths with stone skin stay at 100% dr. The way the wiki phrases it is
>. If a monster already has two (or more) inherent immunities, it can acquire no more from modifiers; if it has less than two inherent immunities, then it is restricted to a maximum of two. Once two inherent and/or acquired immunities have been applied, any % resistance bonuses that would result in further immunities or boost the existing ones are not applied.
Wraiths dont have 2 immunities, but its possible stone skin is still not boosting their dr above 100% anyway.
I think it needs more testing, because theres no clear answer. The bone break buffed lancer was clearly doing about 2x damage to the wraiths under amp, so its having some kind of interaction but that means its either making amp from 20% into 40%, or 100% into 200%- but it cant be 20% into 100% as the game supposes, and the 5% sunder shouldnt make any such difference
We know for sure that amp on bound demons has no penalty even if they are natively physical immune. The example you can test more easily is act 5 urdars with stone skin. Or dark lords. They have 75% dr, so stone skin gives them 125% dr and immune. If amp worked as intended it would set them to 105%, still immune. The bound stone skin urdar clearly becomes very vulnerable, not immune, indicating its set to 25%. So either bound demons get no amp reduction, or maybe like you say, no monsters do at all. But somehow bone break still boosts it? Unless blizzard at some point just capped monster dr at 100 and stone skin urdars are set to 100, and amp takes them to 80. The difference would be pretty obvious from damage output being big or small
This post was edited by Goomshill on Jun 4 2026 09:04am