Euterpian

The Euterpians were an advanced humanoid race.

During the Millennium War, the Euterpians and the Greld used the battle shroud of the Semquess and wielded the Omnethoth, destroying an entire galaxy to destroy a thousand of the Mad Mind's fleets. (PDA: The Quantum Archangel)

Circa 40,000 BC, five Euterpians were stranded on Earth after solar flares destroyed their mothership. They survived the death of their race and homeworld in 8000 BC. Their plans to destroy Earth in 1994 were defeated by the Second Doctor. (MA: Invasion of the Cat-People)