Seymour Boss Fight

[Renmiri]

You get Shiva at Macalania Temple Perhaps this is why you don't have her yet. You should get her right after you defeat Seymour for the first time. (there will be many others, the guy is worse than Jason from Friday the 13th, he always comes back!)

You should probably level up your charcters and Aeons before fighting him if you are having that much trouble. . There are much tougher fights right after this scene as the guado chase you after you kill Seymour... Can you go back to a previous save before you actually talk to Seymour ? If you can, keep on walking around the ice ridges near the temple entrance. They are good enough to level up if you keep running around there for a while... If not, try having Rikku use bombs or grenades to kill the 2 guado fast and damage Anima even before you get Yuna to Summon...

[fushibai99]

You should get shiva befor the battle because the scene befor the battle you see Yuna coming out of the chamber.At first you cant see ????? keep pressing down. :)

[Slade]

Just steal off the two Guados and then they can't use auto-potion. As simple as that
I only figured this out the last time I played the game.