Seymour Flux is soo annoying!
Need help beating up seymour flux? Here is how.
Make sure all you aeons are in overdrive
Start with a party of Yuna, Tidus and Lulu.
Have yuna immediatley cast protect on herself. (if she goes first)
If Tidus goes first, have him cast Hastega.
Lulu should cast Bio.
Yuna should then finish up protect-ing and shell-ing the other party members. Have Lulu switch out for Rikku. Get her to pummel the morti body and seymour.
Once yuna has done her thing, and the mortibodys hp and seymour hp has taken atleast 5000 damage, summon all yunas aeon, and use their overdrives. By now seymour should have around 5000~10000hp.
Finish him off with some magic or physical attacks.
Remeber to finish this fight fast or seymour will use his total annihalation technique
That has a 99% chance to destroy your guys. And make sure to keep you party's hp above 3/4 at all times