Item Bases
Ward Decay Threshold (WDT) is an extremely important stat on this build, as it functions as Health but better, as it's extremely easy for us to regenerate.
As such, our endgame bases almost exclusively consist of gear that provides us with that stat; Necropolis Helm, Necropolis Plate, Arcane Boots, and Ivory Ring all provide WDT, with Ivory Ring pulling double-duty by also providing hefty Necrotic Resistance - our main scaling stat.
Our Opulent Focus and Putrid Souls give us some meaningful Ward per Second, effectively functioning as Health regen within our WDT. Ward retention from the Opulent Focus is not to be underestimated either.
As we struggle to hit resistance caps because of our heavy focus on Necrotic Resistance, I've opted for Spidersilk Sash over Chain Belt, Crusader Gauntlets over Outcast Gloves, and Putrid Souls over Caged Souls. If you're somehow able to overcap all of your resits to 100% without these, please use the other bases.
Luckily, Bone Amulet provides both Necrotic resistance and some Physical damage, so it was kind of a no-brainer.
As for our weapon, Profane Wand is the best choice as it implicitly increases all of our damaging curses DoTs, namely Torment.
Affixes
The main stat we're looking for on all gear (except wand) is SuffixNecrotic Resistance, as it will be giving us the bulk of our defence via WDT, and damage via multiplying Torment.
Other than that, it's pretty straightforward it terms of scaling damage; we look for PrefixNecrotic Damage, PrefixDamage Over Time, and PrefixSpell Damage on most gear, and of course PrefixNecrotic Penetration on our amulet and SuffixNecrotic Penetration and Minion Necrotic Penetration on our wand. Wherever we can't get those affixes, we look for PrefixCast Speed and PrefixIntelligence instead.
PrefixChance to apply Damned on Hit is exclusive on Helmet and Body for Acolytes, so this is an extremely high-value affix. Same for SuffixWard per Second, though its also available on our Catalyst.