Halldon

The Halldons were a race of powerful beings.

History
The Doctor once discovered an account claiming that Halldon scientists had created the Kaledss and the Thals by transplanting primitive humans to the planet Ameron and artificially accelerating their evolution. (RT: We are the Daleks!)

The Halldons fought a time war with the Eternals, which resulted in the Time Lords intervening. (Doctor Who Annual 2006)