Jarra To

 was a scientist who killed the previous overseer of the Axis. She could manifest herself in many forms.

She was in the form of a male jester when she met the Fifth Doctor. In this form she liked the distorted perception that the Axis provided. She suggested that they play for the Doctor's TARDIS in a game. She played games with the Doctor's companions. She met Peri in another form, the form of a bird keeper, and later as a carnival barker. She wanted to give the Doctor his "money's worth", a Grimm's fairy tale. She was a researcher who wanted to reconcile the science and superstition. She craved unpredictability; when the Axis assigned a condemnation notice to her world and put progress on pause, she said that they consigned her to a living hell of always knowing how the story ended. (AUDIO: The Axis of Insanity)