Hath Peck was a Hath who fought in the war against the humans on Messaline.
Peck was caught in a blast detonated by Jenny, which dislocated his shoulder. His comrades kidnapped Martha Jones, who put his shoulder back in place. As the Hath were about to kill her, he stopped them. The Hath discovered that there were secret tunnels in their base so they were forced to raid them to win the war. Martha found a passageway to the top of the planet and went there with Peck. He was afraid to go up, having heard stories about the dangers of the surface, but was fast convinced. As they were walking, Martha fell into some sort of dark-colored swamp or quicksand. Peck saved her by jumping into the muck and pushing her to safety, while he was submerged. Martha was deeply affected by his apparent death. (TV: The Doctor's Daughter)