okay there are two way to get omnislash the long way everyone talk about..but there is a better way. As you may know you only need omnislash to kill the 3rd sephiroth don't worry if you don't know when you get to him becuase when you start the fight you WILL have it no matter what so don't wast time trying to get it just get down their and kill sephiroth's butt (this is just for people who hasn't beaten the game yet)