Brod (A Stitch in Time)

Brod was one of the few remaining normal humans on a devastated Earth in an alternate timeline in the year 5000.

Biography
When the Third Doctor visited this timeline, Brod knew of him from history books in what remained of the British Museum. Brod asked that he use the TARDIS to change history and prevent his world from coming to pass. He travelled with the Doctor to 1872 to try to convince Professor Theodore Cassells to not publish his work, which had led to the global war that devastated the planet.

When Cassells drowned with the crew of the Marie Celeste, Brod vanished before the Doctor's eyes — having been erased from existence along with his timeline. (COMIC: A Stitch in Time)