Mykloz was a Malean.
Maleans were not supposed to have empathy for other beings or affection for each other. Maleans who did so were considered mutants to be destroyed. Mykloz was assigned to kill two Maleans, Orsa and Alëza, who had developed feelings for each other. He chased them to the planet Bukol, where he was defeated by the Sixth Doctor, who had taken Orsa and Alëza under his protection. (PROSE: The Golden Door)
Some time later, Mykloz himself started developing empathy for others. He tried to steal a genetic stabiliser that was in the possession of the Seventh Doctor. He kidnapped the Doctor and then went to private detective Bart Addison, pretending to have lost his memory. He had Addison investigate the contents of the Doctor's pockets, hoping to find the stabiliser. This failed when Addison wasn't fooled by his pretense.
Mykloz was confronted by two other Maleans, Syloz and Harkoz, who accused him of failing his mission of ensuring racial purity in Europe. The Doctor and Addison escaped from the Maleans and destroyed their house and spaceship. (PROSE: Playback)