The Eleven

A Time Lord criminal, using the alias The Eleven in their eleventh incarnation, serves as a recurring antagonist in Big Finish Productions' Doctor Who audio stories, especially those assotiated with the Seventh and Eighth Doctor.

The Eleven serve as the main antagonist of Doom Coalition anthology series, as well as a recurring antagonist in Ravenous, and a recurring antagonist in the second series of The Time War, all featuring the Eight Doctor as the protagonist. The Eleven is his most recurring and well-known incarnation so far.

So far, four actors and actresses voiced the different incarnations of this Time Lord. The Eleven was voiced by Mark Bonnar, the Nine was voiced by John Heffernan, his Octavian disguise was voiced by Tim McMullan, and the Twelve was voiced by Julia McKenzie, who was known for portraying Jane Marple in Agatha Christie's Marple

Personality
The Eleven changes his title which went by a sequential number in each of his incarnations. Being an interesting case in Time Lord villains, the Eleven had a mental illness specific to the Time Lords. The said illness was called the regenerative dissonance, which kept his previous incarnations active inside his mind and bickering against each other.

Each of their incarnations shows a different personality. For example, the Two claims he has an all-powerful nose which can sniff out treachery, the Three is a relentless homicidal killer, the Five is a sophisicated and polite decent man, the Six is a violent and unstable maniac, the Seven is described as a rude and abrasive scientist, the Eight being a much more heroic and kind person who tried to destroy other incarnations for the greater good, the Nine is a full-on kleptomaniac, the Ten is a skilled hypnotist, and the Twelve is a woman better in control of her previous incarnations.

Nothing about the One or the Four's personality and traits are known, except the One was once an elderly human activist before gone rogue, while the Four is weaker than the Eleven.

This Time Lord's most famous incarnation, the Eleven, is a cunning and deadly corrupter. He slips into his previous incarnations when he's riled up. His previous incarnations had methods of dealing with these flareups, but the Eight was the best at it. All of their incarnations, in spite of their disgust and despise towards each other in the Eleven's mind, show a particular hatred towards the Doctor, since it was the Seventh Doctor who sent the Eleven back into prison.

Trivia

 * Some of the incarnations of the Eleven could be considered to be evil counterparts to some of the incarnations of the Doctor (up to the Eighth Doctor). For example:
 * The One sounds noticeably older than the other incarnations, much like the First Doctor, who is the oldest incarnation of the Doctor.
 * The Three is apparently more willing to kill than the others. The Third Doctor was an eager martial artist and had less qualms about handling a gun than his other selves.
 * The Five is polite and amiable gentleman much like the Fifth Doctor.
 * The Six is wrathful and violent, much like how violent the Sixth Doctor was post-regeneration.
 * The Seven is an intellegent scientist like how the Seventh Doctor was an intelligent master manipulator.
 * The Eight is much kinder than his previous incarnations, trying to stop his other selves. The Eighth Doctor is not only much more gentle than the Sixth Doctor and much less manipulative than the Seventh Doctor, but also the exact incarnation of the Doctor who has to deal with the Eleven the most, thus sharing the same goal with the Eight.