Joanna is a young, athletic tomboy with a disdain for the more "womanly" duties that were expected of her as third princess of the Ishalt kingdom. She would often disappear for a long while, much to the distress of her maids, but would tell no one why. It wasn't until her father announced and arranged marriage that Joanna proclaimed that she was giving up her title and becoming a hero, then left in the midst of the uproar. She is headstrong, stubborn, and dislikes being viewed as nothing more than a bargaining chip or ornament.
Despite being a royalty, she doesn't act like it or even like others of her stature. Perhaps it's because her parents left most of her raising to the castle staff, for she seems to be more sympathetic to commoners.