Persephone

Persephone  is the Olympian Goddess of innocence and spring growth. She never makes an actual appearance aside from some minor cameos in the film, however she was intended to make a major appearance in an episode of the animated series, however all the story ideas were dropped as none of them felt appropriate for her. Persephone is the daughter of Demeter.

Story Idea 1
In the earliest known idea Demeter (mother) and Hades (husband) would argue over who got to keep her.

Story Idea 2
In another idea she was going to be a teacher at Prometheus Academy however this idea did not workout either.