plz help

Umm, please try to use better English. I realize you may not speak it natively, but do the best you can. Also, the excessive abbreviations are against the rules. Type your words out, please. That post was really hard to decipher.

Now, are you referring to Seymour or the big dragon thing at the end of the cavern?

For Seymour you want to bring all your aeons out and blast him with overdirves. If he's still alive after that, use all your character's overdives and the strongest attacks at your disposal. You have to beat him as fast as possible, because if Total Annihilation is cast, you're done for. If someone gets low on health, just swap them out and got for the next person. And keep everyone hasted. You want to have as many turns as possible between Seymour's turns.

If it's the dragon, this one is tougher. have all of your aeons' overdrives ready, but don't summon them. You're gonna get one shot with each so make it count. Hit him hard with whatever you can. Use overdrives as soon as you're able, cause he'll cast Curse on you and you won't be able to. You may choose to open with one or two of your weaker aeons' overdrives to get a head start on his HP. But don't overdo it. He casts curaga a lot, and if his HP is low enough that he casts it a lot, he can bring it back up more than you dropped it in those three turns he gets after you use an aeon overdrive. If he starts to cast Curaga on himself too much, cast reflect on him. He's smart, so he'll probably do it to you and then bounce the curaga off your reflect to himself. If that happens, cast dispel on yourself. You may have to do a lot of reflect/dispel casting, on yourself and him to make this work well.

Once you start getting his health down, start blasting him with aeon overdrives. Hopefully you can do enough damage fast enough to kill him. If you can get his health below 10,000, one of the more powerful ones should do it. Get it below 15,000 and Bahamut should be enough. Remember though, you want this to be a one shot kill, or close to it. Otherwise, he'll cure himself, and in the end, he'll have more HP than before you hit him.