It's possible to play as General Leo in places you weren't meant to. Using the airship glitch (which is done by first getting the airship, flying around, getting back to the floating continent, saving, and then dying, giving you use of the airship to travel to any part of the world) you can skip getting a majority of the characters besides a select few. These character's slots will be replaced by characters only used in certain parts of the game, like General Leo.