Annajin Valentin

 met the Fourth Doctor and Oliver Day on Gondovan when they were all on the trail of the Puppeteer, an alien that took over its victims' minds and caused them to act violently. Annajin's brother Sukhrit had been possessed by the Puppeteer, but by the time the three met up, it was possessing Oliver. The Doctor and Annajin defeated the Puppeteer, and Oliver stayed on Gondovan with Annajin. (PROSE: Puppeteer)