The Elders were the inhabitants of a city on an Earth-like planet.
The Elders believed the Savages to be merely a means to an end, a life for them to take. Therefore, they saw no moral dilemma in "harvesting" their life-force until Jano told them of his thesis on equality. (TV: The Savages)
The Elders maintained their advanced society by draining the life-force of Savages that lived outside the city and transferring it to themselves. The Elders knew of the First Doctor, having watched his progress through time and space, and awaited his arrival. Jano, leader of the Elders, wanted to absorb the Doctor's life-force so as to gain his knowledge. During the process, Jano gained elements of the Doctor's personality and so helped the Savages achieve equality alongside the Elders. Steven Taylor stayed behind to unite the two groups. (TV: The Savages)