There doesn't need to be a main character. In fact, I'm of the minority opinion (seemingly) that there just isn't one. You do play as Terra first, but it quickly becomes clear that she's not the valliant knight or brave hero that the main character would be. When she isn't doubting herself, she's trusting someone else, usually Locke or Edgar, even Bannon for a brief time. Locke IS a very brave hero, but the role he plays is usually more significant to himself than it is to the story at large. Edgar only helps get Terra to Bannon, after that he settles quietly into the background. Sabin does even less. He joins up to help out, and then is there pretty much just to fight people and resolve his own personal conflicts. Celes plays a more important role, giving information and doing the Opera House performance, but she too is plagued with self doubt and, let's face it, really couldn't carry any party. She's just not all that powerful on her own. I don't think any one character is the focal point of the game, and I really do like that. It makes the struggle seem more important. Sure, the interpersonal relationships in FFVIII were kinda cool (or they woulda been....) but the main villain is just sorta there for no reason, feeling more like a forced plot device. How many people out there REALLY hated Kefka their first play through?

That's what I thought