Who is Leona from Swan Song and what is their importance?

Leona Skelter is a seer famous for predicting the death of JFK. She shelters Swan and Josh shortly after they emerge from the basement and she reads Swan's fortune, foreseeing great glory and hardship in her future. She gives Swan Crybaby the dowsing rod and sacrifices herself at the K-Mart to give Josh and Swan time to escape from Alvin and his group of insane people.