Stagnant Protocol
The Stagnant Protocol was an interstellar empire ruled by an empress and court of nobles. During the Last Great Time War it was attacked by an experimental weapon that rendered the entire population immortal but sterile, leading the Time Lords to time lock the entire empire.
History
According to the War Master, the Daleks used an experimental weapon on the Stagnant Protocol rendering all its inhabitants immortal, though still able to be mortally wounded, and sterile. The Master believed this to be an attempt to make them more like Daleks. In response, (AUDIO: Unfinished Business) the Time Lords sealed the entire empire in a time lock, leading to the people of the Protocol to believe them responsible for the weapon. (AUDIO: The Sincerest Form of Flattery)
The Master created a gateway into the Protocol and infiltrated the royal court, presenting himself as a Time Lord ambassador. As he began his campaign to takeover the empire, he came into conflict with a rival, Calantha, who had her own designs on the throne. The Master convinced Prince Gardam he could put him on the throne as a champion of the people, however their plans were outmanoeuvred by Calantha who unleashed a virus, which killed the infected slowly and forced them to relive their darkest secrets. (AUDIO: The Sincerest Form of Flattery) The Master recognised this as a weaker variant of a Time Lord virus designed to infect Daleks. (AUDIO: Unfinished Business) Calantha used the ensuing crisis to gain the empress' confidence and had Gardam dispatched to an outer planet of the empire on plague duties. Calantha eventually took the throne herself after the empress died of the virus, leading the Maater to concede defeat in this battle but not the war. (AUDIO: The Sincerest Form of Flattery)
As the plague raged, Nyssa brought a medical ship through the gateway to attempt to provide aid. The Master used her ships facilities to experiment with a variant of the virus, (AUDIO: The Orphan) having acquired a sample of the true virus, (AUDIO: Unfinished Business) from UNIT on Earth. (AUDIO: A Quiet Night In)
The Master unleashed the true virus on the Protocol's homeworld, creating a renewed crisis and forcing Calantha to turn to his aid, appointing him Regent Chancellor. The Master gained influence in the court by listening to secrets voiced by infected nobles he was treating and became popular with the public. Calantha eventually moved against him, secretly imprisoning and torturing him to extract the cure from him. After sometime the Master faked his death, just as Calantha concluded negotiations with a representative of the Daleks who were requesting the gateway be widened so their fleets could pass through the Protocol in return for them helping cure the Protocol's sterility. At the public funeral she organised for him, the Master revealed he was alive and Calantha's dealings with the Daleks, who were truly responsible for the weapon and actually intending to invade. He used his control of the gateway to shrink it as the Dalek invasion force attempted to use it, destroying them, and then revealed Calantha's role in the plague to the outraged crowd.
The Master convinced Calantha to flee the Protocol in a shuttle and ascended to the throne. He announced to the nobles that he would leave them to their own devices for the most part, convinced their fear would keep them obedient. (AUDIO: Unfinished Business)