Optimi

The Optimi were a race of evolving humans who wanted to colonise Zethenda and destroy the Ratlings inhabiting it.

The Tenth Doctor, Martha Jones and the Ratlings activated a terraforming device that created a paradise landscape on Zethenda. This led to the Ratlings and Optimi coming to a compromise: the Ratlings would inhabit the wastelands, whilst the Optimi would live in the paradise they had been searching for. (COMIC: Waste Not)