Doctor Who: EVERY NuWho Villain And Monster Ranked Worst To Best
116. Gat
Appears in: Fugitive of the Judoon.
With colleagues like Gat, who needs enemies - she kills the Fugitive Doctor's unwaveringly loyal companion, Lee, with an unnerving nonchalance, despite clearly having known him on friendlier terms beforehand.
This is the first time we begin to scratch the surface of the Doctor's mind-bogglingly murky past: she used to work for Gat long ago, and they both happen to be from the same neck of the woods, Gallifrey. We also hear the first mention of that oh-so secretive Time Lord organisation, Division.
Given their intriguing shared history, it's a shame that Gat was unceremoniously killed off, because she had scope for further exploration.