Daria Visteron

 was a human scientist from 35th century Earth who was recruited by Rasmus to work at the Deeptime Frontier.

Although her recruitment was seen by the Time Lords as optional, she felt she had no choice to accept, and as a consequence held a grudge against them. With access to Vortex technology, Visteron scanned the Vortex for the Time Lord prison dimension containing the Ravenous, and released them. She claimed to only have wanted to see if the Time Lords could be scared too, and had no knowledge of what the Ravenous could do.

Rasmus eventually promised to take Visteron back to her own time and place, expressing regret for the way he had treated her. (AUDIO: Deeptime Frontier)