ok u ppl here is the easiest way to beat emerald
1-have kotr
2-have everybody with wizard bracelet
3-have everybody with either 4x cut(mastered for all 4) or slash all (not mastered) but preferably 4xcut
4-have all lv 4 limits
5-equip kotr (with an mp turbo) on whoever has the most mp and highest magic (but it dont really matter)
6-its easy if ur limit is already filled before battle (just in case)
7-also have bahamut zero with quadra magic attached equip it on someone other than who has kotr
8-oh and make sure everybody has mime or at least 2
9-when the battle starts use kotr then switch to the third character (the one without bahamut or kotr) and use mime to use kotr another time for another big damage of up to 160,000 damage)
then use bahamut zero (4 times with quadra magic) for a total of up to 360,000 damage
10- repeat this about 3 times and he's dead u should be able to kill him with this technique before he uses air tame strike
and remember its always good to have a few megalixer's
plus if all else fails use a game shark (but thats cheating)