She and Anjeliqua Whitefriar were hypnotised by the Master in 2003 to help him steal the TITAN Array, which he planned to use to rejuvenate himself and destroy the Chronovores. When he used Whitefriar as a test subject, though, she transformed into the Quantum Archangel.
She tried creating separate ideal universes for every being in the universe. However, the Chronovores fed on the universes slowly, corrupting them. Arlene was an extremely popular musician, with a recording career that made Madonna jealous. But as the Chronovores fed, she was attacked by a stalker, then framed for embezzlement. Kairos and the Doctor's TARDIS rescued her before the universe she was in collapsed.