Who is Greta Addington from Fog Magic and what is their importance?

Greta is the young heroine of FOG MAGIC. Even as a baby, Greta feels a special fascination for the fog. She is about eleven years old when she begins to venture into the fog over to the other side of the mountain. She discovers a whole new world in Blue Cove, a fishing community that had reportedly been abandoned years before. Greta's spirit and curiosity leads her into the thick gray fog which she does not fear or detest like the other kids in Little Valley where she lives with her parents. The fog, to Greta, is a protective shield against danger and harm.