TheOriginalChaos
Insanity Is A Gift
First make sure that you have Zombie Ward on all of your armor if not, he'll tear a hole in your face
. Make sure your starting party is Tidus, Yuna and Auron, with Lulu switched in later. (I can't stress enough how important Auron is for this when he's beefed up. Also, Lulu is particularly important for her Bio spell. Make sure that both of them are VERY strong). Now make sure that ALL of your Aeons have their overdrives then start the battle. First use Tidus to cast Haste on Yuna then have Yuna use all of her Aeon's overdrives. On Tidus's turn switch to Lulu and use Bio on Seymour because he can be poisoned easily. With Auron beefed up real high, he can cause serious damage. Once you have used all of your Aeons he should be down to around 10000-2000 hp. After this happens, the rest is just a breeze. Healing is really important in this part, even though it's important overall. Once you beat him you get a shit load of AP and you get a LV.4 keysphere. Good luck. 

