Can someone please tell me how to kill Seymour before he summons Anima?

Ok, for this to work it would be best if you have all overdrive gages full, even the aeons. Now just beat him up until he summons Anima. Now just pound on Anima for a little bit until you have kind of low health. Now bring in Yuna and your heal your party. Then summon an aeon. I prefered Shiva because she was new but it really doesn't matter. Now finish of Anima but make sure you have at least two aeons left, because if you don't it will be quite hard to finish off Seymour. After Anima is gone unleash every overdrive you have left with your aeons and people on Seymour because he is a lot harder now.Follow this and soon he will be dead, kind of, you just wait! Hope I helped!

Just sumon shiva she eliminates anima

You can't beat Seymour before he summons Anima but an easy way to beat Anima is to Summon your new aeon ???? (shiva) and let it use pain and heal yourself with blizzard ( not blizara unless you want to run out of magic) by using blizzard on yourself and unleash your overdrive on it twice. It has 18 000 hp so that only does 3000- 8000 damage a turn. Anima might just uleash his overdrive, Oblivion. It will destroy you. THERE IS NO DOUBT. Don't worry. Just summon either ifrit and heal with fire or ixion and heal with thunder. You might not want to have to use shiva on the first time so it works just as well with ifrit or ixion.

Go to summon aeons with yuna and you will see a "???" on the list
That aeon's overdrive can kil anima pretty fast.

Cast all nunspells on your party before you kill seymour the first time,after that he will summon anima so you will sumon ??? Ke attacking with it and when he does his overdrive use the guard ability to reduce the damaga and then go for the kill.After that seymour will come but you should be in the clear with your nullspells so just keep attacking and this battle should be over with