Either suffer eternally or be erased, not a bad deal I guess. That is, if that elemental is telling the truth.
Anyway, I wonder if there's a link between the two gods, and Merlin and Alice. In both case, there's a good woman (Alice/Maria) and an evil man (Lucifer/Satan). And Alice is using Maria's sword. I wonder if the end here is for Alice and Merlin to become the new gods, or at least to merge good and evil together by becoming husband and wife.