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)