The Grey Lady is the ghost for Ravenclaw House. In life, she was Helena Ravenclaw, daughter of Rowena Ravenclaw, and was killed by the man who later became the Bloody Baron, ghost of Slytherin House.
In Life
Helena Ravenclaw was the daughter of Rowena Ravenclaw, who founded Ravenclaw House and was one of the four founders of Hogwarts. She was envious of her mother's cleverness and importance, so she stole her diadem, believing the item could help her become wise enough to accomplish her goals. Not even her mother admitted to others that the diadem was gone.
The man who would later become the Bloody Baron was sent by Rowena Ravenclaw to find Helena to bring her back to Hogwarts, where Rowena was fatally ill. She tried to hide from him, but he eventually succeeded in finding her. After refusing to go with him, he stabbed her, killing her. After seeing what he'd done, he stabbed himself to death.
The Bloody Baron
The Bloody Baron wanted to marry her, but she rejected his affections and even refused to see her dying mother with him. Due to his hot temper, he killed her in a fit of rage because of her refusal and also because of his jealousy of her freedom.
In Death
Helena Ravenclaw went on to become known as the Grey Lady, ghost of Ravenclaw. The Bloody Baron became the ghost of Slytherin, and wore his chains as an act of penitence, a sign of his remorse for killing Helena.
At some point, Helena told Tom Marvolo Riddle of the diadem she had stolen from her mother, which information he was able to get from her because of his charisma, and also where she had hidden it. As Lord Voldemort, Riddle would turn the diadem into a horcrux.
The Grey Lady
Harry Potter later sought the diadem to destroy it. When he tried to confront the Grey Lady about it, she tried to avoid him, and was hesitant to give him any information. He managed to find out that she had indeed told Tom Riddle about it, and thanks in part to the information she gave him, was able to figure out where Voldemort had hidden the item.
Trivia
- J.K. Rowling has stated that The Grey lady appeared very briefly in Harry Potter and the Philosopher's Stone. Many Harry Potter fans believe this passage refers to her: "[Harry and Ron] passed the ghost of a tall witch gliding in the opposite direction, but saw no one else." Fans have found no other unexplained mention of a ghost in the book, so it is assumed this is The Grey Lady. She makes a more notable appearance in the deleted scenes portion of the Chamber of Secrets DVD (when Harry is finding the secret of Tom Riddle's diary, he asks her for privacy). It seems rather strange that the Ravenclaw ghost is allowed in Gryffindor Tower.
- There are a number of Grey Lady ghost stories of Great Britain, and it is thought that they might have been an inspiration for this character.
(Appears as a ghost or a spirit)
