For years I treated my Fire Druid like a failed experiment. Normal was fine, Nightmare was shaky, and then Hell showed up with Fire Immunes and a smug grin. Terror Zones changed that, and the Flame Rift charm basically finished the job, but gear still matters if you want clean runs and not a sweaty mess. If you're trying to shortcut the gearing pain, you'll see people browsing diablo 2 resurrected items for sale while they theorycraft, because -enemy fire res is the real power stat once everything's sundered.
What actually made the build click
I tested this on the Arreat Summit offline with a level 91 Druid and no "must-have" teleport armor. My first runs were ugly. The damage wasn't the issue. It was how I was casting. A lot of players mash Fissure, Volcano, and Firestorm on the same tile and wonder why bosses live forever. Next Hit Delay is why. If you stack certain fire sources too tightly, you end up overwriting your own hits. So I stopped trying to carpet one spot and started thinking in lanes and zones instead.
Before the altar: set the tempo
I pre-buff, always. Call to Arms if you've got it, then Armageddon before I even click the altar. Armageddon isn't something you "aim," it's just free pressure that keeps ticking while you reposition. It also punishes Korlic's leaps when he decides you're the target. For mobility, I used teleport charges on an amulet. Not to kite, but to start the fight in control. You jump into the middle, pull Talic and Korlic close, and then you leave before they pin you.
The 1-2-3 rotation on the Ancients
1) Drop Fissure right under your feet, then move. Fissure loves moving targets, and Talic basically volunteers by Whirlwinding across it. 2) Swap to Madawc next. He's the annoying one because he hangs back and peppers you, so you plant Volcano directly beneath him. His hitbox is stable, so the pellets connect way more consistently than people expect. 3) When it's just Korlic, I get in close and spam Firestorm. It's messy, point-blank, and it ends the fight fast, as long as you're not standing on your own danger zones.
Gear reality and the "time vs grind" choice
The honest wall for this build isn't surviving Hell anymore, it's stacking enough -enemy fire resistance to make sundered mobs feel smooth instead of spongy. Ravenlore, facets, and a merc helm like Flickering Flame do a lot of heavy lifting, but not everyone wants to live in Lower Kurast for weeks. That's why some players use U4GM to pick up gear or currency and get back to actually playing, then focus their practice on spacing skills, staying mobile, and not letting Next Hit Delay steal their damage.