before the fight put all your units (including Aeons) in overdrive. In the fight move your units so that they don't hit eachother. Suggested units: Yuna to remove bad spells such as berserk (and hopefully you have holy
) Tidus with Blitzace should be strong enough, else you should use his second overdrive, and as third unit Khimari if he has FULL GUARD as overdrive, if not he's useless so pick some1 else. after casting full guard u can use the aeons' overdrive (use it immediateley after summoning because the glyph thingy kills it with one finishing blow). After casting all aeon's overdrives he should be weakened down enough to finish manually. Do NOT EVER attack with Yuna since she has to cast Esuna, use it often, also guard and shell should be cast if the glyph thingy dispels ur SAFE GUARD. Revive when nessecary and you should be allright
oh and yeah, after this boss the trouble starts, unless you do the same I did, put DEATHPROOF and ZOMBIEPROOF on a shield, and your fine
however if u don't have it, do not heal the ZOMBIE state because it's the only thing that protects you from the next boss' ultimate 3-unit-death-move (of course that's not the name, but this is what it does)