Sharon is a member of the spirit race - one of the three races in the game's world alongside humans and demihumans. The spirit race are protectors of an object called the "big pearl of will" (意志の大珠) which has the power to absorb people's desires, whether they are good or evil. Sharon herself was banished from the spirit village for attempting to steal the orb.
Prior to the game's events, Sharon came to a boy named Radius (who would become the primary antagonist of the title) who was angry at the people of the world. She told him all about the "orb of will" and what it could do for him, so one night, he stole it from the spirit village in order to cause chaos among the races.
The party first encounters her in a forest, where she is immediately recognized by Ness's fairy friend, Phillip. She battles them, but loses. Later, in a cave, she captures Fana and ties her to a cross. When Dill, a demihuman rival of Rya, confronts her, Sharon casts a mind control spell on her and tells her to kill anyone who attempts to rescue her captive.
Her last appearance is in the game's final dungeon. Here, Sharon tells the party that she believes only in negative energy and that positive energy is powerless to overcome it. Dill manages to reach the party at the cost of her own life to give the party the ultimate weapon of the demihumans.As Rya cries over her fallen friend, Sharon simply laughs and tells her that she will be joining her shortly. The villainess is battled once again and is killed. In contrast to Radius, she shows no regret for her actions.