Reuben Ncgobo is a member of the African National Congress, who was sent to Moscow for training. He has a wife and four sons in South Africa. At the time of his appearance in the Walter Taffet episode, he had not seen them for a year and a half.
The KGB successfully uses Reuben as bait, to capture NIS officer Eugene Venter. Reuben kills Venter by "necklacing", burning him to death.