Delphi is a very unusual and mysterious young woman. She claims to be the niece and caretaker of Amos Diggory, now a lonely widower in St. Oswald’s, and calls herself Delphi Diggory. She lives at St. Oswald’s Home for Old Witches and Wizards, in a room near Amos’s room. In reality, she is far more sinister, a daughter of evil.
Delphi was raised by Euphemia Rowle, although she was no direct relation. As the daughter of Bellatrix Lestrange, Delphi was the niece of Andromeda and Narcissa Malfoy and cousin of Draco Malfoy. As daughter of Tom Marvolo Riddle, she is the granddaughter of Merope Gaunt and of Tom Riddle Sr. of Little Hangleton.
Delphi is the name of a town in Greece, famous in ancient times for being the location of an oracle which would be consulted before major decisions.