Imogen Frazer

 was the girlfriend of Jerome Khan and a maths student at an English university. In the summer of 1981, a cult that believed that God was a number employed Frazer to search for God. However, they accidentally let loose the I Predator, and it started killing the cultists. Imogen, knowing her fate, made a deal with the I to have her transformed into an I.

Khan, along with Robert DeValley, Aoife Dineen and Donal Dineen came to Fleming's Island to search for Frazer. The Fifth Doctor and Khan eventually realised that Imogen was still alive.

Khan later became an I to be with Frazer. (AUDIO: Iterations of I)