Helena Ravenclaw was Rowena Ravenclaw's daughter. She was a greedy and selfish young woman, which led her to steal her mother's enchanted diadem. She hid it in a forest in Albania while trying to escape her suitor, who killed her and then himself. They became the Gray Lady (the ghost of Ravenclaw House), and the Bloody Baron, respectively. As the Gray Lady, Helena is quiet and struggles to deal with the shame she feels for stealing her mother's diadem in the first place, as well as the shame of having given its location away to Voldemort.
The Gray Lady Character Timeline in Harry Potter and the Deathly Hallows
The timeline below shows where the character The Gray Lady appears in Harry Potter and the Deathly Hallows. The colored dots and icons indicate which themes are associated with that appearance.