I'm unsure if Exodus is that one were several zombies are popping up.

I took all the Espers but Zodiark in no time and only by one try (Zodiark killed me several times lol) I do never use Espers... they suck. I only use that un-spell-able green chuchilin or whatever fat and huge green esper... is fun and tough.

But if Exodus is the one that is in a desert (exiting from those caves) where zombies pop out (you can get platinum dagger from them)... just kill zombies and chain them, when you are done, get out and get in and keep killing zombies... You will have a nice chain and start attacking exodus, you will be killing more and more zombies at the same time and hopefully, you will get cured or MPed from their loot drop.

Its a piece of cake. Watch out for magic elemental attacks from the zombies... and probably clogging or putrid breaths.