Cult of the Heretic

The Cult of the Heretic were a religious group dedicated to worshipping the renegade Time Lord known as the Heretic. Their goal was to regenerate the universe to become its new rulers. Although they worshipped a Time Lord, none of the cult members were Gallifreyan.

The cult was started by the Heretic, who used the cult to construct an anomaly cage. The Doctor stopped the cult from using the Heretic's biodata to regenerate the universe and the Heretic was taken by the Time Lords.

Needing another Time Lord to activate the restart the universe, the cult made a deal with, who had come to offer them his DNA in return for a position of power in their recreated universe. They manipulated him into coming into contact with his, claiming that they wanted him to kill his past self to prove his dedication to their cause. After the Master had crippled his past self, the Cult betrayed the Master by knocking out the future Master and transferring the past Master into his future self, leaving the older Master's mind in his past self. The act of having a Time Lord inhabiting the body of his past self led to the universe beginning to break down. The cult convinced the younger Master that he had just been transferred into the body of his attacker- not identifying the attacker as his future self- and allowed the younger Master to depart. They had intended to kill the older Master directly, but when he escaped their captivity, they hired the Transhuman Sisters of the Unholy Protocol and the Dragonhunters to kill the older Master; while the paradox would still damage the universe as the two Masters travelled around in each other's bodies, the death of the future-in-past Master would ensure that the damage was irreperable.

The Seventh Doctor encountered both of the Masters and helped them get back into the right bodies, although by this point the damage they had caused to space-time had become irrevocable. The two Masters then returned to the Cult's headquarters and killed all of the members. They planned to use the anomaly cage to recreate the universe, but were stopped by the Seventh Doctor- ironically using weapons that the Masters had used earlier and forgotten to reclaim from the Doctor- who made sure that the universe remained practically unchanged by its regeneration, his only change being to save the life of his temporary companion Jemima so that she was never killed by the Master. (AUDIO: The Two Masters)