If a caster knows how to play this--human and drow (and WF) are immune to damage on fire ellie and can take it down (or prep and hold it) better than any class. Cast cold shield, cast damage spell (polar ray or cone of cold) (or 2), cast fire protect, cast cold spell (or 2), cast fire protect, etc. Caster won't take 1 hp of damage. And can take the fire ellie down as fast or slow as the group needs. Once prepped (the caster will almost always have it prepped before the group is done with the other 3), just spam fire protect on yourself until you get the word to drop the ellie.