Originally Posted by
PuPu
You can steal an item from Zeromus' first form called Dark Matter. If you manage to steal it, you can reduce the damage done by Big Bang.
If you are playing the SNES/PS1 version...your battle is much harder. Here, Rosa's Curaja/Cure4 takes longer time to cast the spell. So what'll happen is this:
1. Big Bang will hurt your party by 2000 each almost every turn.
2. Rosa will try to cast Cure4 to heal, but at around level 65, Cure4 only heals the party for 1000 each. It also takes a long time to cast.
3. Zeromus will deal damage with Big Bang faster than Rosa can cure your party with Cure4, and you are screwed.
The only think I could think of doing is having Cecil and Kain, the ones who can survive Big Bang for more than two turns, attack and heal themselves with Elixers when their HP is low.
Fortunately, I don't think you are playing the SNES/PS1 version.
If you are playing the GBA version, just have Rosa keep on using Curaja on the party every turn she gets. Use it even Zeromus uses his next Big Bang; try to time it so that she'll heal the party immediately after Big Bang. Curaja/Cure4 is also faster in this game compared to the other two versions.