I don't even reckon AC even really happened, it was a load of chaos for me to watch, the story was confusing and unbearably poor. FF7 ended with the game, and AC never happened in my eyes.

My opinion earlier was swayed towards Kefka, because the AC Sephiroth got torn apart in a matter of minutes, I doubt if he was this "All powerful, Ultimate form" he would of got beaten so easily, he would of retaliated at the least. So he can avoid and dodge Kefka's attacks? Cloud's can't defeat him? Crap, I say, crap...Sephiroth would of put an end to Cloud's slashing massacre, Omnislash, if he was that powerful.

One Winged Angel is the true ultimate form here, and I believe it would annihilate God Kefka.