[X] Destroy the Hellfire Belchers before they can fire
-[X] Cast another Quickned Searing, Agonizing Firebrand, this time targeting each Hellfire Belcher with one of the explosions, then using the remaining twelve to bombard as many groups of Steel Devils as we can manage, then sacrifice an 8th level spell slot using our Robes of Mysterious Conjuration to Summon an Elder Earth Elemental. Place it above the Hellfire Belchers if they have not yet been destroyed, which instructions to disable them, or if Firebrand dealt with them, drop it on a group of Steel Devils.
This is just a vote for the companions.Your turn is not up yet.