- You may be looking for the Time Lords' enemy in the War in Heaven.
The Enemy was a force created by the Committee that were capable of possession. They wiped the Committee out and waged war against humanity, who eventually forgot their name and what they looked like.
Jeremiah Bash Henderson told the Torchwood Archive that the Archive had drifted into Enemy territory and that he was tasked by Jack Harkness with destroying it to keep the information held within from them. He later revealed that he had faked a "sob story" and this may not have been true. (AUDIO: The Torchwood Archive)