Rydia

When Cecil and Kain burn up the village of Mist, in the beginning, Rydia is the only survivor. Rydia gets hurt, though, and Cecil decides to take her with him. She is the only caller left at the earth since the disaster in Mist, and she can do a lot of powerful attacks. My personal favourite is the Chocobo kick, not that powerful but sure nice to see. Besides her Summon ability, she can also use both black and white magic. And that’s always useful, you know.