Medea
Medea is the daughter of King Trode and the princess of Trodain. She's arranged to be married to Prince Charmles of another kingdom, Argonia — although she hasn't met her fiancé before.
She's a horse now, though. You see, that awful Dhoulmagus turned her into one when he stole the magic sceptre from Trodain and cursed the kingdom, and its king. She pulls the cart carrying her father around.
To be honest, I'm glad she's a horse. You see, once you get a hold of the Alchemy Pot, it too resides in the cart. She's much more useful pulling it around for you than she would have been as a princess. Chances are pretty good that if she remained human, you'd have to spend most of the game rescuing her.