Ah, so I'd need to keep my Fire Res <= 50%. Hmm. Mythril Targe, Cursed Coronet, Sage Cloak, Fire Amulet, Evil Eye Jewel, Fire Affinity... Maybe swap the Amulet for the Lantern, and the Gastro for the Targe...
That's 300% Fire Amp exactly, along with ~26 Attack without Curse... And the weakest Multi Target Fire damage is 12 from Condensed Fire Formulae...
When would I ever want to use Lava Bombs? Mythril's expensive?
Then there's the Stone's Throws + Nature's Boon, then there's defeating Enemy 135... At least 45 Attack without Curse. But really, if I can defeat Enemy 135, haven't I proved myself?
And you're somehow running a 30 Attack...