Colin Frazer

Colin Frazer was the cousin of Tegan Jovanka. While he and his friend Robin Stuart were vacationing in Amsterdam in 1983, they decided to spend a night in the abandoned Frankendael mansion, having arrived a day early and found no room at the hostels. Colin was abducted by the Ergon and forced to work on helping Omega return to corporeal existence. He was later freed by the Fifth Doctor. (DW: Arc of Infinity)

It is unknown if he is the nephew of Tegan's aunt Vanessa (DW: Logopolis) or the grandson of her maternal grandfather Andrew Verney (DW: The Awakening).