If you mean Jecht Braska's Final Aeon he's actually really simple. The trick is to level up all your characters so they cover at least half the sphere grid. i did that by putting overdrive mode comrade on all chars, then triple or double AP and Overdrive to AP on all chars. Must customize items for the last 2. then go and fight Cactuar King in the beast arena over and over. Keep all your chars alive but do not attack him!!!!!! Then go to Jecht and hit him 3 times with Anima's normal attack and he should be dead. My Anima did 99,999HP per hit.

Quote: destinygirl

how do u beat sin the very last sin at the tower of the dead help plz

you must have anima or you cannot win then lvl your characters until you have them at about 4000 hp a peice kill his first form with all aeons (apart from bahamut and anima) when he goes second form he will do 3000 to all party members heal then hit hbim with bahamut and anima if this does not take him down a few casts of ultima or firaga should do it (if you have double cast use it!!)