-45% from Mystic Orbs cubed with jewelry (2x rings and amulet);
-(6 to 15)% from Six Angel Bag;
-(22 to 40)% from 2x rare rings;
-(21 to 30)% from a rare amulet.
Lowest roll will give you -94 fire resists if you go with
Defense: (4795-5382) to (5289-5935)
Chance to Block: 3%
Required Dexterity: 440
Required Level: 100
+(41 to 50) Energy Factor to Spell Damage
100% Chance to cast level 19 Rain of Bombs on Melee Attack
2% Chance to cast level 27 Beacon when you Kill an Enemy
40% Increased Attack Speed
1% Increased Chance of Blocking
+(31 to 40)% to Spell Damage
(21 to 25)% Bonus to Energy
+(301 to 350)% Enhanced Defense
+10 to Light Radius
instead of a rare paladin shield, so your goal is to either farm yourself a Six Angel Bag charm with good -resists roll or reroll better jewelry.
NOTE: Chaos Ladder won't allow you to reroll rare jewelry, but the min. and max. amount of -resists were increased so its easy to stack -100 pierce anyway.
Considering -199% fire/lightning resists, I used full Malthael's set that already gives -100 pierce and gear mentioned above. In Chaos Ladder the set was nerfed (-60 pierce now) so, imo, its better to go with Fascinating/Ornate crafted gear against heroic bosses since crafted gear bonuses was dramatically buffed.