Estelle Stiles is a tourist in Rennes-le-Chateau during the events of Gabriel Knight 3. She is a companion of Lady Lily Howard. It is strongly suggested that the two are in a lesbian relationship, though this is never said directly.
Stiles is in Rennes-le-Chateau helping Howard find the treasure. She and Howard live in Stiles' modest home, but Stiles would like to provide a life of luxury for Howard. To this end, she wants to find the treasure of Rennes-le-Cheateau, which she believes to be material wealth.