Mary is the pseudonym of a translucent humanoid who possessed the body of a 19th century prostitute named Mary. She was a member of a race, possibly called Arcateenians, from Arcateen V, which communicated exclusively via telepathic pendants, and claimed to be a political exile, sent to Earth by a teleporter now in Torchwood's possession. At one point, "Mary" calls herself Philoctetes, in reference to his exile on Lemnos. She gave her telepathic necklace to Toshiko, and seduced her into letting her into Torchwood to regain the teleporter.

On arriving on Earth in 1812, the alien killed her guard and possessed Mary. In this form she needed to consume human hearts to maintain the host's youth, taking one a year. "Mary" threatened Tosh in order to regain the teleporter and Jack exchanged it for Tosh.

Death: Jack had reprogrammed the coordinates of her teleporter, sending "Mary" into the Sun instead of back to her homeworld.

"Mary" possessed strength large enough to shatter human bones in a manner resembling a gunshot and could move at superhuman speeds, also possessing acute senses – she was able to notice that there was something different about Jack.

Daniela Denby-Ashe was born, 9 August 1978, London

Her father came to Britain from Poland at age 12, and her mother was raised in France by Polish immigrant parents. She has a brother, two years her junior. Daniela studied ballet and tap as a child, and began acting at age ten.

Torchwood

Greeks Bearing Gifts (2006) TV episode .... Mary

Before Torchwood

"My Family" .... Janey Harper (64 episodes, 2000-2008)
Maxwell (2007) (TV) .... Andrea Martin
The Family Man (2006) (TV) .... Kelly
North & South (2004) (TV) .... Margaret Hale
"The Afternoon Play" .... Kate (1 episode, 2003)
"Rescue Me" .... Julie Carter (1 episode, 2002)
Magic Hour (2002) (TV)
"Office Gossip" .... Cheryl (6 episodes, 2001)
Is Harry on the Boat? (2001) (TV) .... Lorraine
"Fish" (2000) TV series .... Jess Taylor (unknown episodes)
"EastEnders" .... Sarah / ... (260 episodes, 1995-1999)
Absolutely Fabulous: Absolutely Not! (1998) (V) (as Daniella Denby Ashe) .... Saffy's Daughter Victoria
"Absolutely Fabulous" .... Saffy's Daughter Victoria (1 episode, 1995)
"The Bill" .... Debbie Higgins / ... (2 episodes, 1994-1995)
Molly (1995) (TV) .... Marie
"Kevin and Co" (1992) TV series .... Sophie Coe