Asha Gryvern worked for Professor Martez as his "faithful assistant". When Professor Martez was to be put on trial, Martez transferred his brainwaves into Asha's body, and pretended to be Asha. Asha's body was later killed by one of the "Mutant Daleks" Professor Martez had created. (AUDIO: Blood of the Daleks)
Behind the scenes
Although Hayley Atwell only plays Professor Martez after putting his mind in Asha's body, for both parts of Blood of the Daleks, Atwell is credited on the Big Finish website as "Asha" and in the narrated credits of the story as "Asha Gryvern".