Kefka is more likely to laugh at Sephiroth.

Sephiroth: I was to use Meteor to be a god and so I brought the Black Materia to myself at Northern Crater, summoned it and then made a big barrier around it while I prevented the Planet from stopping Meteor. And...

Kefka: Yada-yada-yada. So you wanted to be a god? I was one. I had a giant tower made out of random crap and enjoyed leisurely vaporizing towns. You had a big hole in the ground and a big rock...and both of it did crap.

Kefka would kill Sephiroth while laughing. And the true FF fans rejoice.