How does an old Arreat helm work?

[d2lover]

i believe the wording on the item is "15% targetdefense"

what happens if the target has stoneskin or (in pvp) a coldarmor?

I have collected some of them and wanted to ask if they are usable outside of PvP.

 

[art_vandelay]

The modifier in question is called "reduce-ac" and its value is to be interpreted as a percentage. In 1.07-1.09 the target defense is set to the value specified by "reduce-ac" while in 1.10a+ target defense is reduced by the value specified by "reduce-ac".

Arreat's in 1.07-1.08 has "reduce-ac" 15 while Eth in 1.07-1.09 has "reduce-ac" -25. In 1.10a this changed so Eth has "reduce-ac" 25.

That means for regulars/minions:
1) 1.07 Arreat's in 1.07-1.09 sets Defense to 15%.
2) 1.07 Arreat's in 1.10a+ reduces Defense by 15%
3) Eth in 1.07-1.09 sets Defense to -25%. (effectively giving Ignore Target Defense)
4) Eth in 1.10a+ reduces Defense by 25%.
I assume penalties against players/bosses/pets would still apply.

No clue on interactions with Stone Skin/Cold Armors.

1.07-1.08 Arreat's doesn't have Crushing Blow so it sucks anyway in 1.07-1.09.