The Deindum were a species who, if allowed time travel, would have rivalled the Time Lords.
Irving Braxiatel and Doggles attempted on several occasions to destroy the Deindum before they evolved into sentient creatures, but on each occasion they were stopped by Deindum from the future. (AUDIO: Escaping the Future)
The Deindum tried to make Deimos and Phobos leave Mars' orbit in the 21st century. Merlin sent Excalibur to Winifred Bambera and Ancelyn in order for them to use the sword to prevent the Deindum's plan from succeeding. (PROSE: Excalibur of Mars)
Bernice Summerfield discovered that during the industrial age of the Deindum's development, they were contacted by Deindum from the future and were given time travel technology. Shortly after they gained the ability to travel in time, the Deindum's biology was altered by Braxiatel to make them a weaker species.
With time travel, the Deindum conquered the universe and wiped out the human race.
Because their appearance was different when the Deindum contacted their past, Bernice Summerfield and Braxiatel manipulated the situation to portray the future Deindum as con artists and a war broke out between the future and past Diendum. The war caused the Deindum to be destroyed at a point before they developed time travel and thus failed to conquer the universe. (AUDIO: Escaping the Future)