what is the interaction with demon machine and mirrored blades?
Mirrored blade projectiles don't have nextdelay and can shotgun on the same target, and their explosions can also shotgun. But they only carry +fire damage on the char onto the explosions
So you can get your choice of some permutation of
>mediocre physical damage x 5 projectiles that shotgun per-target
>good magic damage x 5 projectiles that shotgun per-target
>terrible fire damage x 5 explosions that shotgun 5x-per-target
With an enchant sorc of course it goes nutty. But the +magic damage from hex bane is only applying to targets you hit directly, not the shotgunning overlapping aoes of exploding arrows
so for example if you hit 5 enemies with 5 arrows with 10 more clustered enemies, they all get hit by 25x your fire damage, but only the 5 hit take 5x your physical/magic damage
There aren't really many ways to load up on fire damage. Maybe you could have some stupidly contrived +fire sc build. You can get +205 from horazon's gloves, +31 per facet, 40 on the uber jewel. You can maybe get some extra from +% fire included above demon limb or full horazon set, but its still about ~99-150. Kuko is +110 but only 50% pierce / 7 exploding.
but yeah you have to go pretty deep to even hit ~1200 fire damage