This article contains plot details from the latest book.
The Foster family is the human family that raised and took care of Sophie. They believed Sophie was their biological daughter and did not know that she was an Elf or a Telepath. They do not remember Sophie however, because they had their memories wiped on Sophie's request. Sophie wanted them to forget her so they wouldn't have to live through the pain of missing her, like she had to miss them. The Elves had planned on faking Sophie's death. Sophie watches her family with her illegal Spyball, given to her by the Black Swan.