Caleera

The Red Lady - previously known as Caleera and the Sonomancer - was a Renegade Time Lord who was splintered across all of time. Before becoming the Lady, she was a powerful natural psychic who was manipulated by Padrac in his plan to destroy most of the universe.

As Caleera
As a student in the Time Lord Academy, her tutors thought that she wouldn't amount to anything. She was a powerful telepath and she wanted to learn how to control it, but her tutors wanted to suppress the powers. She was placed as an assistant to the junior archivist on leaving the academy. She used her powers to empathise with Helen. In her time in the archives she interviewed the Eleven, who convinced her to amplify her powers to use in his plans. She was in love with the Eleven. (AUDIO: Scenes From Her Life)

Caleera kidnapped Stormblood from the archives shortly before the Eleven's escape from Gallifrey. (AUDIO: The Crucible of Souls)

Liv Chenka and Helen Sinclair found her trapped in a TARDIS and wanted to help her escape. (AUDIO: Scenes From Her Life)

As the Sonomancer
She experimented with her powers to create a curse for the people of San Francisco which would amplify the earthquake of 1906. She then gave the gift to the Eighth Doctor, who used it to save Liv from dying. (AUDIO: The Gift)

In her power she became the Sonomancer. She decided to use this power to destroy worlds and proceeded to destroy Syra. The Doctor tried to stop her from destroying the planet by trapping her in the mining station. She used her power to call the Eleven's TARDIS to save herself and the Eleven. (AUDIO: The Sonomancer)

After escaping Syra she inhabited The Matrix. She used the timing of the Doomsday Chronometer to start her plans and to get plans for the Resonance Engine. She didn't like River Song. She trapped Livia's ship in the transduction barrier and later destroyed it. She took River into the Matrix and tortured her. (AUDIO: Songs of Love) The Eleven asked her to use her powers to help the Weeping Angels by creating darkness. (AUDIO: The Side of the Angels)

Padrac placed her in the Resonance Engine in order to amplify her powers so that she could destroy the universe. The Doctor tried to convince her that Padrac would discard her once his plans were completed. She went into the matrix and found out that Padrac had manipulated her into this decision. Using her connection to the Matrix she fed Liv and Helen a message, first for Liv to destroy the Capitol shields and then to Helen to pilot a Battle TARDIS into the Resonance Engine. She then became the Red Lady. (AUDIO: Stop the Clock)

As The Red Lady
When the Doctor first met Caleera as the Red Lady, she was a mysterious creature that appeared in the art of many civilisations. She later attacked Albert Kennedy. She was referred to in all of the documents that Liv Chenka and Helen Sinclair translated. She would kill anyone who saw her. (AUDIO: The Red Lady) She did this as she was trying to find Padrac so he could pay for what he did to her. (AUDIO: Stop the Clock)