- You may wish to consult
Theta
for other, similarly-named pages.
Commentator Theta Sigma was a version of the Doctor who existed in an alternate timeline where Rassilon failed to finish the Eye of Harmony before his death. Consequently, Theta Sigma never left Gallifrey. He became a commentator rather than a renegade Time Lord. (AUDIO: Forever)
In the proper timeline, "Theta Sigma" was the Doctor's nickname at the Academy. (TV: The Armageddon Factor, The Happiness Patrol)