Violet Hopley was an Earth girl.

In 2007, an escaped Extron criminal came to Earth and hid in her bedroom. Before the Tenth Doctor could stop it, it kidnapped Violet and took her to the planet Onla-toch.

The Doctor managed to find her and gave her biometric handcuffs he had gotten on Inkarsera, from where the Extron had escaped. While it was attempting full gene transmutation using her energy pattern, she put on the handcuffs, which transported the Extron back to Inkarsera. The Doctor then returned Violet home. (COMIC: The Monster Upstairs)