Eternal

Not possessing the power of creativity themselves, the Eternals utilise the thoughts and emotions of so-called Ephemerals (time-bound beings) for their own ends.

Characteristics
The Eternals dwelt in the domain of Eternity rather than the smaller one of Time. Unaffected by Time and thus unaging, as their name would suggest, the amoral Eternals make it their principal aim in life to amuse themselves, using Ephemerals as their toys. (DW: Enlightenment) In the course of their games, the Eternals would sometimes pose as gods and doom whole worlds in the process (DWM: Uninvited Guest). These games were started by the Guardians of Time, whom the Eternals greatly respect as leaders. Though they are related to the Chronovores, they looked down on them as vicious predators. The Ancient Compact prohibited a union between the two beings. However, the great Kronos arose from one of such union. (PDA: The Quantum Archangel)

Through somewhat obscure means, as a punishment, the Doctor used the force of the Time Vortex itself to bring the particularly callous Lord Prospero and his social circle into the domain of Time, which would indicate that under circumstances they can transition from Eternal to Ephemeral. (DWM: Uninvited Guest)

Powers
Eternals could use telepathy and create objects from the memories or Ephemerals. They could also make objects vanish. (DW: Enlightenment) They could also appear in dreams. (NA: Love and War)

History
The Eternals were, as their name suggests, eternal, therefore a history of their race would be hard to find. However, the first event that they are known to have done was to banish the Carrionites into the Deep Darkness. (DW: The Shakespeare Code)

Until he met the Doctor and probed his mind, the Eternal known as Striker professed that he had never heard of the Time Lords. (DW: Enlightenment)

On the Time Lord homeworld Gallifrey where they passed themselves off as the natives' deities such as Time, Pain and Death, a development which Lord President Romana found distressing. (NA: Happy Endings)

The carnage of the Last Great Time War horrified even the aloof Eternals to the extent that they left this reality. (DWA: Doctor Who Annual 2006)

Other information

 * The Eternals referred to the Void as "the Howling". (DW: Army of Ghosts)
 * Sebestiene claimed to have hunted down an Eternal. (TDA:The Doctor Trap)