For FF6 humour, look no further than the combined might of Kefka and Ultros.

Above anything else, I love comedy, and now that you mention it I'm just about noticing that FF is very short on it. At least the earlier instalments had plenty of Engrish, and who could forget this classic from FFT:

Quote Originally Posted by FFT, most probably Professor Daravon in particular. Fool.
Many became rebels plotting rebellion against (the royal family or the nobility or something, I don't remember because I was laughing at "rebels plotting rebellion")