Esti is an teenage Israeli girl, with a long dark brown pony tail, featuring red highlights, as well as tanned skin and brown eyes. Initially she was seen wearing a light blue vest, but is later seen wearing a t-shirt in her team colours of white and green.
Esti is introduced as part of a group of outcasts living on the beach just outside of the Greenhouse, alongside her friends; Daria, Mori and David. Later it's revealed she was orphan.
Later after the discovery of the secret Sparrows team, Esti and her friends form the team, with Daria later leaving.