The Goblins stay where they are and produce 4 magic results.
They lack the punch to do anything serious to the elf army, so they bring back an old friend.
Unsurprisingly the reserves produce nothing to assist.
They would be better employed fighting dragons.
With (eventual) help from friends.
The dust storm blows out and the lava elves take control of the vortex. This means that from now onwards, a unit at this terrain will get a second chance with any action except manoeuvre.
With help from the vortex, the elves achieve 6 missile result.
No saves from the goblins.
No magic from the reserve army either.
They have a change of plan. Pole pole, as they say in Africa.