Vivi vs. Kefka

[Khuutra]

Eh

Kefka tends to cast Fallen Angel in the middle of battle, then also follows that up with Ultima or Forsaken

Vivi might be able to do it if he was a combo-specc'd melee character from FFVI, but as he is in FFIX? Not a chance, even if he just cast Doomsday nonstop (Kefka is the fastest enemy in the game)