Who is Gillian Teys or Nell Grahame Clarence from A Great Deliverance and what is their importance?

Gillian Teys resembles her mother, Tessa. She is quite petite, with short blond hair that makes her look significantly younger than she actually is. Gillian is the oldest daughter of William Teys and the sister of Roberta Teys. Gillian is a chameleon; someone who behaves according to the expectations, wants, and wishes of those around her. Gillian Teys ran away from home at the age of sixteen, the age Tessa was when she married Gillian's father. Gillian is currently married to Jonah Clarence, a young minister and the son of the founder of Testament House, a facility for runaways located in London. Gillian engages in compulsive behaviors having to do with being clean. This is her response to having been molested by her father for the better part of her life.