The Doctor of the Doctor Who TV series, played by multiple actors because he periodically "regenerates," is a member of a humanoid alien race called the Time Lords, from the planet Gallifrey, whereas the Doctor played by Peter Cushing in two feature films is a twentieth century English inventor whose surname really is "Who." Thus, this version of the Doctor remains closer to his Wellsian origins.
Although Poul Anderson's Time Patrol is founded by the post-human Danellians, it is staffed by human beings recruited from a million years of pre-Danellian history. Manson Everard, a high-ranking Unattached agent of the Patrol, deals directly with the "Middle Command," presumably human. Everard is privileged to meet one Danellian at the beginning of his career and another later. Their appearances are so different from each other that the Danellians might be shape-shifters.See Time Travel Synthesis.