I’ll say that I am not very good with strategy so how do I do this. I really have enjoyed the game up until this point but this battle is a like a big speed bump that I just can’t get past.
i just filled the overdrives for all the aeons and it also helps if yuna has the ability to perform holy. lost the first time, but seconds always a charm.
Unfortunately I don’t have Holy and it might take a while to get it if I tried.
-Wantz sells items with Zombie Ward, they may help.
-Start off with Bio (please tell me you have it..)
-You could use Mighty Guard if you have it (though your only chance to learn it before this point is from Biran Ronso, so if you didn’t get it from him… then you won’t have it ’till after Flux).
-The unsurvivable "Total Annihilation" is actually the little Mortibody’s skill (or whatever he’s called then), and not Seymour’s himself, so killing Morti while he’s "preparing" for Total Annihilation should cancel it, even though he comes back to life. I don’t know if you reached this point yet, you said he had a lot of HP even after the aeons.
It was actually Cross Cleave that got me most. It’s annoying how Esuna and Remedies don’t remove Zombie, but there’s always Holy Water. You can use that and then take advantage of his curative spells that follow.
Wakka’s Attack Reels is also just as good as the Aeons if you have it.
Another thing you could do before unleashing the Aeons is Auron’s Banishing Blade, which will inflicts all the "Break"s.
Now I can finally go on with the story!