I've been noticing throughout the story, that the villains (even Jecht) seem to have retained all or most of their knowledge of things prior to being called to battle. They don't appear lost or hampered by their new situation in the slightest, whereas the Cosmos team is always discovering new things about their plight. They guide the heroes; they even toy with them to some degree, dropping hints but never fully revealing the purpose behind their battle. I could be entirely wrong, but my interpretation of some of the Chaos side's musings leads me to believe they're unaffected by the same amnesia the Cosmos warriors suffer from.

From what I recall when I had Dissidia, was that the villain's suffered some form of amnesia, perhaps not as bad as Cosmos's side though. I recall seeing two villains... Kefka and someone else mentioning that Sephiroth killed himself in front of them and that was so Sephiroth would retain his memories in the next crossover (I'm guessing that happens in Dissidia Duodecim, though don't know for sure.).

TBH, never really paid much attention as it's a spin off title.

http://www.youtube.com/watch?v=PaC-3Hh0wzA&feature=related

Watch this. Kefka's story will tell you all you need to know.

As you can see, the villians do get their memories erased during the purification. However, they have had the upper hand during the last few cycles, that is why the remember so much more then Cosmos' warriors.

I always did have a sense Kefka had a slight upperhand ;) His sheer awesomeness gives him that as it is ^^ That's the most fun I've had in minutes! He's the purest evil of the entire Chaos bunch.

Agreed!

Garland has no finesse, The Emperor lacks Kefka's maniacal demeanour, Cloud of Darkness cares only for the void and therefore doesn't really take an active role, Golbez even goes so far as to aid Cosmos' warriors, Exdeath is just completely pathetic, Sephiroth couldn't care less, Ultimecia just plays second fiddle to The Emperor, Kuja doesn't want to get involved and Jecht was originally Cosmos' chosen; so all in all, Kefka's mania stands out dramatically in the twelfth cycle. His schemes seem to be the only ones that work, mostly because he tries the hardest.

As you can see, he even plots against his own 'comrades'. The only loyalty he has is to himself and that is what makes him truely evil, when one considers all he has done.