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Warning! This page contains spoilers for The Ship of the Dead.
Percy mentioned his unborn half-sister to Apollo, saying that he would like to meet her.
Estelle is a female name originating from the southern region of France and surrounding countries known as Occitania. It means ''star''.
- Estelle is named after her maternal grandmother.
- As Sally Jackson has Clear Sight, the ability to see through the Mist, it is possible that Estelle will inherit this ability as well.
- Given that Sally was seven months pregnant in The Hidden Oracle, which takes place in January, Estelle was probably born in or around March.