I had a Guide to Beating Sephiroth in here once... but it got deleted in the MASS PRUNING!!!

I'm too lazy to ever write it again, but the other EoFFers should have enough skill to piece it together. What I can tell you is that you need to have MP Rage equipped twice. Also, remove all your Combo Plus and Sky Combo Plus for this fight, and allocate those points to other things. Sephy teleports if you try to use a combo greater than three, and we don't like teleport.

Also, despite what other people say, GUARD! It truly does prevent the damage. And Guard/Counter works well during his Omnislash. if timed properly, your counters will intercept his slashes.