Ailla (The Dark Path)
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Ailla was the Master's companion and lover when he was still known as Koschei. While he believed her to be a human from the 28th century, she was actually an agent of the Celestial Intervention Agency sent to spy on him. When Ailla appeared regenerated[statement unclear] after Koschei had destroyed an entire planet to try to bring her back, it proved to be too much for him. Her betrayal and his murder of a planet was believed to have been the catalyst for turning Koschei into the Master, who sought to control the universe. (PROSE: The Dark Path)
