Ok, this is an easy one. Make a party of 4 villains from FF, CT/CC, BOF, ect, excluding any characters not or barely related to the story.

I'm thinking Sephiroth, Golbez, Magus, and Kefka. Sephy has the pure physical power and pretty good magic, Golbez is probably the most powerful black magic caster in existance, Magus has some serious magic firepower and decent physical str, and Kefka... well, tis difficult to deal with an insane clown turned god, no?