Who is Keeper from Entwined and what is their importance?

Keeper is the man the girls meet when they step into the silver forest and onto the pavilion. He invites the girls to come and dance at the pavilion whenever they want. As the novel unfolds, Keeper reveals his true identity to Azalea, he is the former King who steals the souls of the people who die. Keeper also has magical powers. One of his powers is to transform himself into other people by drawing from a possession that belongs to the person.