The Grey Ghost, or Lady Shade, is an evil ghostly entity. It first appears in Ghost Story.
She looks like a grey-cloaked figure with green-white eyes of fire. When her hood fell back, her face looked like a "hatchet", both cheeks marked with ritual spiral-shaped scars, her hair was long, whit and in irregular patches. Her skin was wrinkled and leathery and loose around the neck like a lizard. But her eyes were gorgeous like a "James Bond villainess", a vibrant green with long lashes. Harry Dresden wondered if this was the real Corpsetaker.
The Grey Ghost can use magic. She had been a member of the White Council sometime before the French and Indian War. She knew Council level magic. As the Grey Ghost, she developed Council level wards hidden amongst gibberish script.
In the series
In Ghost Story, during the attack of the lemurs and wraiths on Mortimer Lindquist's house, the Grey Ghost appeared out of nowhere and zapped Sir Stuart Winchester with lightning from clawed hands. He deflected one of Sir Stuart's bullets with magic. The Grey ghost had with him a Skull with blue eyes floating in the air behind him.
Dresden's ghost sneaks into the Big Hoods and the Grey Ghost's hideout behind an army of wraiths. He finds the Grey Ghost is torturing Mortimer to force his permission to enter his body—a requirement—by repeatedly putting him down into a pit of Wraiths, Big Hoods and lemurs watching. Dresden witnesses her making a deal with the Fomor Lord Omogh's agent, Listen, to kill the Ragged Lady, and help the Fomor enter the Fortress. Dresden deduces that the Grey Ghost is the Corpsetaker and her getting a body with magic capability is a very serious threat. Lea told Dresden what she knows about Corpsetaker and her plans.