Rafando

Rafando was a humanoid who lived on a planet reputed for its carrying out of death sentences. (TV: Extremis)

Rafando tried for some of the many "crimes against the universe" she had committed across her past lives, (PROSE: Missy on Trial) and was then tasked with carrying out her execution after she was found guilty.

As only another Time Lord could action the mechanism devised to execute a Time Lord permanently, he was forced to track down the Twelfth Doctor and ask him to bring down the lever, noting that "his species was hard to come by". The Doctor initially seemed to go along with the butchery, but deactivated the machine at the last moment. Rafando protested and was told by the Doctor to check his entry in the Fatality Index under "cause of death". Seeing the seemingly-endless list of "fatalities credited to [him]", Rafando quickly lost cool and fled. (TV: Extremis)