how in the hell can you beat the sancuary keeper he just keeps casting cureaga.

I don't think he is immune to zombie so just hit him with a zombie attack from aruon or just use your aeon's with their overdrives already ready for battle.

thanks for the zombie thing but the proble is my aeon's overdrives were all the way up and they are very powerfull,yet i still cant beat him.

When it came to him I casted reflect on him(makes him waste a turn casting reflect on you)...and kept using my Aeons so that I didnt get hit with Photon wing(whatever it is). I kept Rikku and yuna out because he would use reflect on one of my characters so when I had them out I was almost always able to pull that character out before he reflected the curaga on himself. Just make sure your overdrives are all the way up and go from the the slowest aeon to the fastest...because when he starts losing lots of life he will use reflect and curaga. Hope this helps