The Warkeeper was an alien who lived in the Slough of the Disunited Planets. He was the controller of the Hawks.
The Warkeeper called the Tenth Doctor and the Brigadier in to see him. By that time, he was extremely old and on the edge of death. He wanted the Brigadier to replace him as the new Warkeeper. As the horde of creatures broke in, he started to die. He was left alone with the Hawks, but the Hawks eventually woke up and left him unguarded, and the harpies killed him. (COMIC: The Warkeeper's Crown)