The Hawks were stone warriors who fought on the Slough of the Disunited Planets.
The Hawks were a clone race made by the Warkeeper to protect the Warkeeper's castle from a horde of creatures. They could be controlled by whoever wore the Warkeeper's crown. They were lead by the Hawk leader.
As the Warkeeper got closer to death, the Hawks became less powerful and eventually froze as he could not control them. After the Warkeeper died, the Hawks were taken over by Michael Yates, who had been forced to be the new Warkeeper by the Harpies. The Hawks were teleported to Upper Wardleswick where Yates planned to use them to declare war. The Hawks fought against a clone army of Brigadiers created by the Tenth Doctor. However, the Hawks were dissipated along with the Brigadier clones after Yates commanded all clone material to be destroyed. (COMIC: The Warkeeper's Crown)