Zoria
Zoria (PROSE: Hello And Congratulations!) was a mysterious agent with unknown superiors, going by gender-neutral pronouns, who continually used the Time Fracture to find "very specific people" and went to "very specific places". (WC: Is anyone receiving these transmissions?)
Biography
During an adventure which they were forced to repeat at least one million times by a time loop after entering the Time Fracture, a human learned "Zoria's secrets". The Doctor was also aware of these. (PROSE: Hello And Congratulations!)
After UNIT Sergeant Robert Dudley was left stranded in Elizabethan England after travelling through the Time Fracture, (WC: This is Sergeant Robert Dudley., Dudley here.) he spent five years in the court, where he had noticed a "mysterious agent" who had been "collecting various parts", though he wasn't sure what they were doing or building. He spoke about other information he knew about the agent in a transmission to the UNIT Black Site, even though he was unsure if it still existed. (WC: Is anyone receiving these transmissions?)
Behind the scenes
Zoria was a major character in the Time Fracture interactive story, where she was presented as a Time Lady from the Last Great Time War, scheming to resurrect Rassilon. Depending on the performance, she was played by Ivy Corbin, Jessica Hern or Chioma Uma.
In the webcast Is anyone receving these transmissions?, Robert Dudley makes reference to an agent who is gathering parts to build something. With the context of the Time Fracture play, the agent is clearly Zoria, who was revealed to be gathering components to construct a "Temporal Disruptor" to reset the universe so the Time Lords could preside over a new one.