Ketha

Ketha was a planet, and the homeworld of an ancient order of ruthless warriors known as the Death Lords.

The Death Lords were sworn to protect Ketha. During their last stand when the Citadel was lost, the Elders having betrayed them, the Death Lords turned against their leader Vakrass and he was left for dead, drifting through the blackness of space until he eventually became the "last of the Death Lords." The Eighth Doctor later reflected that they had "died out" a long time ago. (AUDIO: The End of the Beginning)