Is abyss magic dmg? Sorry im not familiar with warlock at all
yes, and can hit about -75% pierce (10 consume defiler, 7 gheeds, 8 hellwarden, 5 per sling, 20 ars dul mephistos, 10 uber jewel, 10 renewed sundered), while players can only get magic resist from horazons normally (30%) but if they really stretch can use crafted safety shield (10%). Only sorcs can imaginably get the bane's wraithskin bonus since it uses enigma's armor slot (30%). And there's no % magic absorb on items. So usually people have either -75% or -45% resist vs abyss warlock
and the only char who
can stack magic resist... is another warlock, using consume on wyand voidbringer, once per game with limited duration, the only source in the whole game, and a warlock with some swap gear and ~34 consume winds up hitting +112% resist / +10% max magic resist / 54% magic pierce... and still be at 67% resist vs the abyss necro and take about 247 per direct hit / 516 per second.