The Grey Lady is better known as the Ravenclaw ghost at Hogwarts School of Witchcraft and Wizardry. She remains unnamed for the greater part of the Harry Potter series, drifting in and out of the story until Harry Potter and the Deathly Hallows, in which it is discovered that she is Helena, the daughter of Rowena Ravenclaw herself.

When Helena was still alive, she stole the diadem of Ravenclaw from her mother; the diadem is known to bestow wisdom upon the wearer, and Helena hoped to make herself “more important” than Rowena. She fled to Albania, where she hid the diadem in a hollow tree.

Heartbroken, Rowena sent “the Baron” after Helena because she knew that, as he had loved Helena for a long time, he would stop at nothing to find her. Eventually, he did find her hiding in a forest, and when she refused to return with him, he grew angry and stabbed her in the chest.

Centuries later, a young Tom Riddle was able to charm Helena’s ghost into revealing the diadem’s whereabouts; the diadem later became a Horcrux containing a portion of Lord Voldemort’s soul.

As a ghost, Helena is described as being a tall, beautiful young woman with waist-length hair. She wears a floor-length cloak and has a haughty, proud look about her.

Helena, according to BabyNames.com, is a Greek name meaning light.

In the films, the Grey Lady is played by actress Nina Young.