Dissidia: Final Fantasy (the official title) has a 28+ character cast with all of the main heroes and villains from every past Final Fantasy game from the core series of titles.
That includes Final Fantasy I and II, Final Fantasy III, Final Fantasy IV, Final Fantasy V, Final Fantasy VI, Final Fantasy VII, Final Fantasy VIII, Final Fantasy IX, Final Fantasy X, Final Fantasy XI and Final Fantasy XII.
Dissidia also brings one new character into the mix. The game itself is essentially a 3D brawler in which your character has a myriad of moves that they can pull off. However the game also contains some of the traditional RPG trappings that the series is known for.
——> NOTE: We also have a guide that explains how to unlock all Dissidia Final Fantasy secret characters.
Here is the list of heroes and villains that appear in Dissidia: Final Fantasy for PSP: (note: Not all are playable)
HEROES
1. Warrior of Light (FF1)
2. Firion (FF2)
3. Luneth AKA Onion Knight (FF3) — he has 2 forms: Monk & Ninja (FF1)
4. Cecil Harvey / Paladin Cecil / Dark Knight Cecil (FF4)
5. Bartz Klauser (FF5)
6. Terra Branford (FF6)
7. Cloud Strife (FF7)
8. Squall Leonhart (FF8)
9. Zidane Tribal (FF9)
10. Tidus (FF10)
11. Shantotto (FF11)
12. Cosmos (Dissidia: Final Fantasy)
VILLAIN
13. Garland (FF1)
14. The Emperor [Palemacia] (FF2)
15. Cloud of Darkness (FF3)
16. Golbez (FF4)
17. Exdeath (FF5)
18. Kefka Palazzo (FF6)
19. Sephiroth (FF7)
20. Ultimecia (FF8)
21. Kuja (FF9)
22. Jecht (FF10)
23. Gabranth (FF12)
24. Chaos (FF1)