C is for... Carrionites

An incredibly ancient race, who derived their power from words rather than numbers. Embarking on a war with another powerful race which threatened the nascent universe, the Eternals stepped in and banished them to the realm of the Deep Darkness.
A trio of Carrionites escaped and found their way to London in the late 16th Century. They had with them a crystal sphere in which their race were imprisoned. They took on humanoid female form, adopting the names Lilith, Doomfinger and Bloodtide. Maintaining this form took a lot of energy, and so they appeared as wizened old women. The younger of the three - Lilith - was also the strongest, and she was able to retain the appearance of a beautiful woman for much of the time. To the locals of the period they would be seen as witches, and their word-science would have sounded like witchcraft.
They were able to influence people's minds so long as they had a piece of their genetic material to work with. A few strands of hair would do, attaching them to a crude facsimile of their victim to create a DNA replication module.
They thrived on blood, and Lilith would ensnare young men on whom they would feed.

They planned to free the rest of their kind from the Deep Darkness by exploiting the words of the playwright William Shakespeare, preying on the emotions he felt at the loss of his son. They first made the architect Peter Streete design the Globe Theatre with 14 sides - reflecting their home planetary system of Rexel 4. They then set about influencing Shakespeare to write a play - "Love's Labours Won" - which would contain the words needed to unlock the prison in which the rest of the Carrionites were held. When the Master of Revels threatened to stop the play being performed, Lilith stole a lock of his hair, attached it to one of their DNA replication modules and immersed it in a barrel of water - causing him to drown on dry land.
Peter Streete was driven mad by his contact with them, and they killed him in Bedlam to stop him helping the Doctor, Martha and Shakespeare - causing his heart to stop. When the Doctor identified their species, he used the power of their name to attack them. Knowing he posed a threat to their plans, Lilith stopped his heart - not realising he was a Time Lord and so carried a spare.
The play was staged at the Globe, and at the climax the cast said the lines that had been inserted. Carrionites started to materialise in their true form - large skeletal raven-like creatures.

The Doctor had Shakespeare create new words to use against them, with Martha throwing in a final "Expelliarmus!" from J K Rowling, to cast them all back into the crystal sphere and the Deep Darkness. The Doctor took the sphere and kept it locked away in a locker in the TARDIS.

Played by: Christina Cole (Lilith), Amanda Lawrence (Doomfinger), and Linda Clark (Bloodtide). Appearances: The Shakespeare Code (2007).

• The Carrionite sphere is seen again in The Unicorn and the Wasp (by the same author - Gareth Roberts) where it is being held in a locker containing things beginning with the letter 'C'.
• Prior to this Christina Cole was best known for playing another witch character, in the TV series Hex.
• The story is full of Shakespeare in-jokes. The three Carrionites are obviously based on Macbeth's Three Weird Sisters.
• The name derives from carrion - the decaying flesh of dead animals - and the birds which feed upon it, such as ravens and crows, which influence the design of their natural forms.