Doctor Who: Victorious

Doctor Who: Victorious is the second special between Series 6 and the Darth/Gear Series. It is a feature-length special that deals with the Doctor and co. bearing witness to an alternate reality where the Doctor has devolved into a mass-murdering, megalomanic tyrant and the entire universe is under his control. The 'Whoniverse' Doctor must do battle against himself to topple his dictator counterpart's rule and prevent him from extending his oppression across even more universes.

Synopsis
"The Doctor's most defining trait was his heart. Taking that away from him brings the birth of an evil beyond any ever seen." - River Song

An unspecified event in an alternate version of the Doctor's life causes him to abandon his former life and instead controls and dominates the entire universe singlehandely, seeing his power and his rule as the only way to preserve peace and order. The real Doctor, Rory, Amy and River must stop the Victorious from unleashing hell onto their reality as well.