Daniel Hopkins

Daniel Hopkins was a UNIT medical officer from the 1980s. He assissted the Fifth Doctor in investigating the Helliax and Annabel Mordon. He turned down a request to travel with the Doctor due to the oncoming birth of his child. (AUDIO: The Helliax Rift)

Unfortunately, a few years later, Hopkins' family was killed in a house fire, an event which drove him mad with grief. To this end, he betrayed UNIT and became a sleeper agent for the Cybermen. When the Doctor returned in his sixth incarnation to aid UNIT in investigating the Cybermen's plot, he killed Lt-Col. Lewis Price and brought the Doctor to the Cyber Leader. He was consequently converted into a Cyberman himself. (AUDIO: Hour of the Cybermen)