All of them. I think they all portrayed different aspects perfectly (or as close to perfectly as possible).
Eiko: Lonely (although she tries her best to be strong, it becomes apparent that she always felt like crying but never did because she wanted to be strong... what a trooper). Yet finds friendship in Zidane and co.
Vivi: Lost, confused. Finds out what it means to die and what it means to live (and that by living, you're also dying and all that heavy stuff).
And etc. o.O; I'd love to write one for them all but just reading each character quote really does define them greatly.
