The Enigma

The Enigma was a race that existed in a different dimension, which had no concepts that the main dimension had.

The Enigma could create illusions such as "Shadow Daleks" and alter timelines. The Daleks used the Enigma to erase the Time Lords from history, replacing them with the Daleks. It took Leela to communicate with the War Doctor and Ollistra. Ollistra asked it to destroy the Daleks instead, whilst the Doctor requested it remove both the Time Lords and Daleks from history to prevent a possible future Time War. The Enigma ultimately decided to do neither. (AUDIO: The Enigma Dimension)