Carrionite

The Carrionites were species of humanoids which used word-based science or "witchcraft" to reshape reality.

Biology
The true form of a Carrionite resembled a giant skeletal raven or crow. They could assume a more humanoid form but this expended a lot of energy and thus they usually had wrinkled skin, large clawed hands, and sharp canine teeth (Doctor Who: The Encyclopedia). However, the Carrionite Lilith could assume the form of a beautiful young woman, a trick she used to ensnare male victims. The Carrionites summoned by the final lines of Love's Labour's Won were even more horrific, with no visible legs, massive claws, beak-like noses and hooked chins. (DW: The Shakespeare Code)

Technology
Carrionites could fly, dematerialise and rematerialise at will, communicate with other Carrionites from a distance and use puppets to cause odd deaths in enemies. Though their abilities were described as witchcraft, it was actually based on a word-based science, as opposed to the mathematics of most species. This technology relied on the right words and the right places, such as the Carrionite's use of Globe Theatre's structure. (DW: The Shakespeare Code)


 * The fact their science was largely implemented using words alone, without much use of instrumentality, suggests that their powers were derived from the lexical equivalent of block transfer (which used pure mathematics to reshape reality).

They placed great importance on the knowing the names of an individual, which would allow them to take control of them. The Carrionites also appear to be possess some unknown ability to discover a person's true name; although Lilith was in the room when the Doctor and Martha Jones introduce themselves to Shakespeare she later remarks "there is no name" when trying to name the Doctor. (DW: The Shakespeare Code)

History
At "the dawn of the Universe", the Carrionites evolved in their 14-planet star system and developed their word-based science. (DW: The Shakespeare Code)

Eventually, the Carrionites got into a war with the Hervoken. This war threatened the structure of the universe, so the Eternals stepped in and banished them to the Deep Darkness. (NSA: Forever Autumn)

Several million years later in the late 16th century, a group of three - Bloodtide, Doomfinger and Lilith - escaped using words of power from the plays of William Shakespeare, partly the result of the writer's grief at the death of his son. They influenced the design of the 14-sided Globe Theatre, based on the planets of their star system, and, in 1599, planned to use his new play, Love's Labour's Won, to free the rest of their race from the Darkness and take over Earth, removing Humanity from it as a pestilence, to establish the "Millennium of Blood".

The last few lines of the play were written by Shakespeare in a trance to be a spell said by one of the cast of the play to open a portal from the Deep Darkness to this universe. However, the portal was closed and the race of witches and all copies of Love's Labour's Won vanished into the Darkness thanks to the help of the Doctor, who told him that he was "the wordsmith" and could create the new words of power to send them back into the Darkness, and Martha Jones, who provided the last word - "Expelliarmus" - from the Harry Potter series of novels.